According to William Ames (1576–1633), the work of angels is “to celebrate the glory of God and execute his commandments (Ps. 103:20), especially for the heirs of eternal life” (Heb. 1:14; Pss. 91:11; 34:7). (A Puritan Theology: Doctrine for Life, p185)
Regarding angels’ specific function, there are at least four:
1) Angels continuously worship and praise the God they serve (Job 38:7; Psalm 103:20; Isaiah 6:1–3; Revelation 4:8; 5:9–12).
2) Angels communicate God’s message to man. They assisted in bringing the Law (Acts 7:38, 53). Angels revealed the future to Daniel and to the Apostle John (Daniel 10:10–15; Revelation 17:1; 21:9; 22:16). Gabriel announced the births of both John the Baptist and Jesus (Matthew 1:19–24; Luke 1:11–28; 2:9–12).
3) Angels minister to believers. “The angel of the Lord encamps around those who fear him, and he delivers them” (Psalm 34:7). “For he will command his angels concerning you to guard you in all your ways; they will lift you up in their hands, so that you will not strike your foot against a stone” (Psalm 91:11, 12). Angels have dramatically delivered believers from prison (Acts 5:19; 12:6–11). Angels rejoice at the conversion of sinners (Luke 15:10). They are present within the Church (1 Corinthians 11:10). They watch the lives of believers with interest (1 Corinthians 4:9; 1 Timothy 5:21). They carry believers away at death to the place of blessedness (Luke 16:22).
4) Angels will be God’s agents in the final earthly judgments and Second Coming. They will call forth the elect with a loud trumpet from the four winds (Matthew 24:31; 1 Thessalonians 4:16, 17) and will then separate the wheat from the chaff (Matthew 13:39–42). The book of Revelation tells us they will open the seals, blow the trumpets, and pour out the bowls of wrath. They will also execute the judgment against Satan and his servants (Revelation 19:17–20:3, 10).
(R. Kent Hughes)