1 Tim 6:9 Those who long to be rich, however, stumble into temptation and a trap and many senseless and harmful desires that plunge people into ruin and destruction. 6:10 For the love of money is the root of all evils. Some people in reaching for it have strayed from the faith and stabbed themselves with many pains.
6:11 But you, as a person dedicated to God [lit. ‘O man of God’], keep away from all that. Instead pursue righteousness, godliness, faithfulness, love, endurance, and gentleness. 6:12 Compete well for the faith and lay hold of that eternal life you were called for and made your good confession for in the presence of many witnesses

3:16 Every scripture is inspired by God and useful for teaching, for reproof, for correction, and for training in righteousness, 3:17 that the person dedicated to God [lit. ‘the man of God’] may be capable and equipped for every good work.

The highlighted phrase is lit. ‘a/the the man of God’.  These are the only two places in the NT where this expression occurs.

1 Timothy 6:11

Here, the phrase clearly refers to Timothy.  What is less clear, however, is whether it refers to him as a private Christian believer, or as a commissioned leader.

Marshall discusses both interpretations, without appearing to adjudicate:

‘There are two main ways in which the designation can be taken in the present passage. First, it is simplest to align Timothy as God’s representative and a Christian leader with the OT prophets and similar people who were called to be prophets (Roloff, 345f.). But the designation is not just functional and unrelated to character (pace Hasler 49); dedication to God’s service with its consequent obligations is included. It would be correct to say that the language is applied to Timothy because he falls into this class; it is not a designation confined to him. Some scholars then generalise the reference to include any ‘ordained’ church leaders like Timothy; no doubt the reference can be generalised to include any such people, but we should be careful not to link it anachronistically to formal ordination. Another view is that the term specifically describes certain people as being Spirit-inspired or charismatic persons exercising a ministry in the congregation (Brox, 212f.; Holtz, 139; cf. Knoch, 45). But the claim that this is the force of the term in Hellenistic Judaism seems to be unsubstantiated, and Roloff argues that church leaders are not thought of as ‘pneumatics’ in the PE.

Second, the term may refer to any Christian (Karris, 35; Merkel, 49f.). This is the force in 2 Tim 3:17, since here Timothy is being addressed as a typical believer (2 Tim 3:12) rather than as a church leader (pace Roloff, 345f.; so rightly Sand, A., EDNT I, 103, but he thinks that in the present verse it is ‘a title associated with his office’). Since the context is baptismal, it is tempting to see here a phrase addressed to the newly-baptised although confirmatory evidence is lacking. In any case Timothy is addressed as a leader whose way of life is to be an example to all believers, and what is said to him can be applied to them all (Knight, 260; Oberlinner, 289).’

The scholarly consensus, however, tends towards the viewing Timothy as an authorised minister.  For example, Lange comments:

‘This name places Timothy, as a Christian prophet, by the side of the chosen messengers of the Divine will in the Old Testament (comp. 2 Peter 1:21).’

EBC:

‘This is a common designation for prophets in the OT (e.g., 1Sa 9:6; 1Ki 12:22; 13:1). There has been much discussion as to whether it carries that connotation here or is used as a general title for all Christians (cf. also 2Ti 3:17). In any case, it refers to someone who is in God’s service, represents him, and speaks in his name.’

Padilla:

‘This appellation has a distinguished history in the OT, being used of Moses (Deut. 33:1; Josh. 14:6; 1 Chr. 23:14), Samuel (1 Sam. 9:16), Elijah (1 Kgs 17:24), David (2 Chr. 8:14), as well as other prophets (1 Sam. 2:27; 1 Kgs 12:22; 13:1). It was an honour for Timothy to be called a man of God.’

Yarbrough:

‘This is the only time the expression occurs in the NT. For Jews like Paul and Titus, it would resonate with the same words that appear in over sixty passages of the LXX.882 Moses is “the man of God.” So are various prophets like Shemaiah (1 Kgs 12:22), Elijah (1 Kgs 17:18, 24; 2 Kgs 1:9–13), Elisha (2 Kgs 8:4), and David (2 Chr 8:14; Neh 12:24, 36). Paul’s language evokes a startling correlation between figures in OT times who received unusual commissionings (on Timothy’s call, see v. 12) and enablements from God and his young(er) understudy Timothy.’

Liefeld:

‘[This expression] appears a number of times in the Old Testament, including references to Moses (Deut. 33:1; Josh. 14:6; Ezra 3:2; title to Ps. 90), Samuel (1 Sam. 9:6), David (2 Chron. 8:14; Neh. 12:24, 36), Elijah (1 Kings 17:18), and Elisha (2 Kings 4:7). At first glance it seems to refer to strong leaders. But while it may have been used in this way for King David, the two references given for him use it in connection with his instructions concerning the role of the Levites in worship. It should be noted that the expression in the New Testament uses the generic anthropos (“human being,” not “man” in the sense of male).’

Mounce:

‘The expression ἄνθρωπος (τοῦ) θεοῦ, “man of God,” occurs sixty-eight times in the LXX. It is used as a title for Moses (e.g., Deut 33:1; Josh 14:6; 1 Chr 23:14), David (Neh 12:24), and prophets (e.g., Samuel [1 Sam 9:6, 10]; Elijah [1 Kgs 17:18, 24; 2 Kgs 1:10, 12]; Elisha [2 Kgs 4:7, 9]; unnamed [1 Kgs 13 (9×); 21:28]; and an angel [Judg 13:6–8]; cf. N. P. Bratsiotis, TDOT 1:233). It is used of Timothy (and other Christians by implication; cf. similar δοῦλον … κυρίου, “servant of God,” in 2 Tim 2:24). Its use here is explained by the need to contrast Timothy with the opponents. They are people who teach incorrect doctrine, promote unhealthy instruction, have a sickly craving for controversy, are corrupt in the mind, are greedy for gain, have abandoned the faith, and have inflicted their own wounds. But Timothy is a man of God akin to the prophets of old with the authority to fight the false teachers of Ephesus.’

Lea & Hayne (NAC):

‘Bernard states that Paul’s appeal to Timothy as a “man of God” reminded Timothy that he had received a divine message just as had the Old Testament prophets (see Josh 14:6; 1 Kgs 12:22). It pictured Timothy as one with a special calling for God’s service.’

Fee:

‘The vocative, man of God, although somewhat unusual (cf. 1:18; 6:20; 2 Tim. 2:1), is used again as an appellation for Timothy as minister of the Word of God in 2 Timothy 3:17. The background for the term is the OT, where in each case it refers to one of God’s servants or agents: Moses (Deut. 33:1; Josh. 14:6), David (Neh. 12:24), or one of the prophets (1 Sam. 9:6; 1 Kings 17:18; 2 Kings 4:7). It is probably called forth here as a sharp contrast to the false teachers, who, by having abandoned Christ, have also ceased to be servants of the Word of God.’

Towner:

‘The calling to serve God is a calling to a position of special honor. Paul designates Timothy (and equally all faithful ministers) as man of God, a title given to Moses (Deut 33:1), David (Neh 12:24), Elijah (1 Kings 17:18) and Elisha (2 Kings 4:7) in the Old Testament. In so doing, he sets the minister apart as one having a special relationship with and an origin in God. The minister is God’s special representative, one whom God has personally chosen and sent.’

Douglas Milne:

‘‘Man of God’ is a title from the Old Testament for the Lord’s servants (Deut. 33:1; 1 Sam. 9:6f.; 1 Kings 13:1, 4ff., 7f.; 2 Kings 4:9, 16, 21f., 25ff.; 5:8; Neh. 12:24). It indicates that this person is entirely at God’s service in proclaiming his word and living in obedience to his will. Timothy, as a minister of Christ under the new covenant, belongs to this noble line of faithful servants of God (Phil. 2:19f.; 2 Tim. 3:17).’

JFB offer a nuanced interpretation, commenting that the reference is:

‘primarily Timothy as a minister (cf. 2 Pet. 1:21), just as Moses (Deut. 33:1), Samuel (1 Sam. 9:6), Elijah, and Elisha; but as the exhortation is as to duties incumbent on all Christians, the term applies secondarily to him (so 2 Tim. 3:17) as a Christian born of God (Jas. 1:18; 1 John 5:1), no longer a man of the world: raised above earthly things; therefore God’s property, not his own, bought with a price, so having parted with all right in himself: Christ’s work is his great work: he is Christ’s living representative.’

Hendriksen makes a distinction between the OT and the NT usage:

‘In the old dispensation this was a designation of the person who by God had been entrusted with a high office (Moses, Deut. 33:1; Ps. 90:1; David, 2 Chron. 8:14; Elijah, 2 Kings 1:9; the prophets, 1 Sam. 2:27). In the new dispensation, now that every believer is viewed as a partaker of the anointing of the Holy One, and therefore as a prophet, priest, and king (1 John 2:20; cf. 1 Peter 2:9), the description is used with respect to any and every believer, as is clear from 2 Tim. 3:17.’

2 Timothy 3:17

Here, there is greater uncertainty.  Opinion varies about whether ‘the man of God’ refers to:

(a)Timothy, in his role as a Christian leader;
(b) male Christian leaders;
(c) Christian leaders, both male and female;
(d) all believers.

In the first three cases, the reference is to the people whose role it is to teach, reprove, correct, and train in righteousness.  In the last case, it is to the people receiving this instruction.

This variety is reflected in the various translations:

NIV84, ESV, NASB, AV, NKJV, RSV – ‘the man of God’
NEB – ‘the man who belongs to God’
NIV2011 – ‘the servant of God’
NET – ‘the person dedicated to God’
GNB – ‘the person who serves God’
NRSV – ‘everyone who belongs to God’
TNIV – ‘all God’s people’

TNIV and NRSV lose both the robust individualism and the focus on the Christian teacher.

Indeed, with reference to the TNIV translation, Bill Mounce counters:

‘In my opinion, “all God’s people” is an impossible translation of “the man of God” (o tou theou anthropos), even with the singular footnote, “the servant of God.” Paul is thinking primarily of Timothy, a fact totally obscured by the TNIV’s attempt to not use “man.”’

Lea:

‘He used “man of God” as an oblique reference to Timothy. The statement in the verse holds true of any Christian leader’

Laansma:

‘Either this expresses the purpose or result of the four functions just mentioned and so applies to all believers (NLT), or it relates more particularly to the leader (Timothy and the “trustworthy people”) so that the equipping consists in enabling the leader to perform these tasks. Timothy was addressed personally as a “man of God” in 1 Tim 6:11, but the general concern with “salvation” (3:15) and “every good work” (here) weighs against restricting the clause to leaders.’

Hendriksen:

‘The man of God (see on 1 Tim. 6:11) is the believer. Every believer, viewed as belonging to God, and as invested with the threefold office of prophet, priest, and king, is here given this title.’

Lange:

‘The man of God (1 Tim. 6:11); a special description of Timothy (see the place) here, of the Christian generally, as of a man who is born of God through the Holy Ghost, and is affiliated with God.’

Guthrie:

‘There may be an allusion to the work of the prophets in the use of this title, for it was frequently applied to them in the Old Testament.’

Yarbrough draws attention to the OT background:

‘“Servant of God” translates Greek “man of God” (see 1 Tim 6:11 and comments), the only other place in the NT the Greek term appears. The phrase is used over sixty times in the LXX to refer to figures including Moses, Samuel, Shemaiah, Elijah, Elisha, several unnamed prophets, and David. Like Timothy, these men were called to leadership through prophetic gifting (see 2 Tim 1:6; also 1 Tim 1:18; 4:14). The expression would be meaningful to Timothy with his OT knowledge (2 Tim 3:15), though it has relevance to all who share Timothy’s faith in Christ (again, v. 15) and recognize the God who gives Scripture (v. 16).’

CBC:

‘Either this expresses the purpose or result of the four functions just mentioned and so applies to all believers (NLT), or it relates more particularly to the leader (Timothy and the “trustworthy people”) so that the equipping consists in enabling the leader to perform these tasks. Timothy was addressed personally as a “man of God” in 1 Tim 6:11, but the general concern with “salvation” (2 Tim 3:15) and “every good work” (here) weighs against restricting the clause to leaders.’ (CBC)

Stott is undecided:

‘It may be a general term for every Christian, since the words themselves mean no more than ‘the man who belongs to God’ (NEB). On the other hand, it was an Old Testament title of respect applied to some of God’s spokesmen like Moses (Dt. 33:1), David (2 Ch. 8:14) and Elijah (1 Ki. 17:18), and Paul specifically addressed Timothy by this phrase in his first letter (1 Tim 6:11). It may therefore refer here to men called to positions of responsibility in the church, and especially to ministers whose task it is, under the authority of Scripture, to teach and refute, to reform and discipline.’

Fee remarks that although the phrase might point to those receiving the teaching,

‘the context, plus the use of the title man of God in the singular, almost demand that Paul is, rather, concerned with Timothy, as the one responsible for giving the instruction.’

Nicole (EDT, art. ‘Woman, Biblical Concept of’) remarks that ‘the language [Paul] uses is that of generic humanity and applies to women as well as to men.’

Marshall (ICC) thinks that the phrase

‘can be used of any believer, although the thought here may be especially of Christian leaders.’

Mounce (WBC) translates ‘person of God’, explaining:

‘The phrase is directed specifically to Timothy, a “man of God” (1 Tim 6:11), and to all Christian leaders, but by implication to all Christians (hence, “person”).’

Conclusion

Taking into account the OT background, and the clear reference, in 1 Timothy, to Timothy himself, I am inclined to think that the reference to ‘the man of God’ in 2 Timothy is also to Timothy, especially in his role as an accredited minister.  These texts can be applied by extension to other Christian ministers.  However, they do not by themselves resolve the issue of the assumed gender of ministers.