1:13 And when you heard the word of truth (the gospel of your salvation)—when you believed in Christ—you were marked with the seal of the promised Holy Spirit, 1:14 who is the down payment of our inheritance, until the redemption of God’s own possession, to the praise of his glory.

Compare the same passage in the Authorised Version:

‘In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise, Which is the earnest of our inheritance until the redemption of the purchased possession, unto the praise of his glory.

See also:

Ephesians 4:30 And do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption.

2 Corinthians 1:21–22 ‘But it is God who establishes us together with you in Christ and who anointed us, who also sealed us and gave us the Spirit in our hearts as a down payment.’

When does this ‘sealing’ take place?

It has been variously argued that it takes place:

(a) At conversion.  The reception of the Spirit is, above anything else, what marks Christians out as God’s people.  Paul has been stressing that God has blessed us with every spiritual blessing in the heavenlies, and it would not be consistent with this for him so soon afterwards to imply that there is a class of believer who has not been so blessed.    Indeed, we are surely expected to include the sealing of the Spirit as one of those spiritual blessings with which we have been blessed.

Guy Duffield (Foundations of Pentecostal Theology):

‘When we are saved, God places His seal of ownership upon us…The seal of God’s ownership of His saints is the presence of the Holy Spirit indwelling their hearts. This is an earnest or pledge that they are His, until the day when He shall return to take them unto Himself.’

According to Beeke and Jones, Calvin held this view, as did John Owen.

(b) At baptism.  According to Smalley (NBD, 3rd ed., art. ‘Seal, Sealing’), this was the view of R.E.O. White (The Biblical Doctrine of Initiation).  W. F. Flemington thought that baptism itself was the seal.  So also Dunn.

There is no reference to water baptism either here or in the related passage in 2 Cor 1:21f.  Smalley, nevertheless, notes that the Holy Spirit and baptism are frequently linked in the NT (see, for example, Acts 8:36ff.; 10:44), and therefore proposes that:

‘this “sealing” by the Spirit takes place at baptism, or more precisely, perhaps, at the moment of commitment that finds its focus and expression in the sacrament of baptism.’

(c) at a time of ‘second blessing‘ during the Christian life. This has been argued by many Pentecostalists, and by D.M. Lloyd-Jones (following Thomas Goodwin, Charles Simeon and Charles Hodge), who declared:

‘I assert that this ‘sealing with the Spirit’ is something subsequent to believing, something additional to believing.’

According to Beeke and Jones (A Puritan Theology), Richard Sibbes taught a double significance:

‘Sibbes distinguished between the office or function of the Spirit as a seal given in regeneration to a sinner and the work of the Spirit in applying that seal to the believer’s consciousness.’

The case for regarding the ‘sealing’ as referring to an experience of the Holy Spirit subsequent to conversion relies heavily on translating the present passage ‘after you believed’ (cf. AV). Just as faith is logically, but not chronologically, prior to justification, so belief is logically, but not chronologically, prior to the sealing of the Spirit.

It also relies on certain passages in the book of Acts; but it is probably best to regard these as transitional, rather than normative, for the Christian’s experience of the Holy Spirit.

Moreover, this runs against Paul’s argument at this point, which is that these Gentiles in becoming Christians also received the promised Holy Spirit, thus showing that they belong to God too; how could the apostle say with confidence that they (presumably all receiving this letter) had all received such a second blessing?

Though the experience to which Lloyd-Jones and others refers cannot be supported from this text, and does not take the form of a separate and distinct ‘second blessing’, nevertheless the experience itself may well be authentic, and receives scriptural support from Eph 3:14–19 (cf. Rom 8:15–16; Jn 14:18–23).

Lloyd-Jones asks:

‘How can the Holy Spirit be a seal if we do not know it experientially? How can it be of value as a seal to us if it is only something that we have to accept and believe by faith, with the experiential aspect entirely absent? The whole point of the seal, according to the teaching of Scripture, is that I may know this, that I may enjoy it, that I may have the assurance and this blessed security of my ultimate complete redemption and perfection.’ (Great Doctrines of the Bible, Vol 2).

(For a friendly critique of Lloyd-Jones’ teaching, see this article, by Barry York.  More generally, see the discussion in NDT, art. ‘Holy Spirit’, by J.I. Packer)

According to Beeke and Jones, a mediating position was held by the Puritan Paul Baynes, who:

‘distinguished between being sealed by the Spirit (which all believers possess) and being made conscious of such sealing (which only those who are conscious of the graces of the Spirit possess).’

Conclusion

I incline to view (a), although I recognise that a link with baptism may be implied.