The hand of the Lord is an anthropomorphic description of God’s effective power (see Luke 1:66). It is possible that it includes a reference to signs and wonders which confirm the message about Jesus (see Acts 2:43; Acts 4:30; Acts 5:12; Acts 6:8).1 In any case, the Holy Spirit was working powerfully as the Word of God was proclaimed.2
21 And the hand of the Lord was with them, and a great number who believed turned to the Lord.