1:3 infallible proofs. “Infallible proofs” is one word in the Greek (tekmerion) and occurs only this one time in the New Testament. It emphasizes that the evidences for Christ’s resurrection were not philosophical speculations but certain facts! It is appropriate that the word occurs only once, for no other event of Biblical history has been confirmed more certainly than His bodily resurrection. Not only His ten or more appearances to the disciples, but also the otherwise inexplicable evidence of the empty tomb, the remarkable change in the disciples, the development and spread of the church as a result of its preaching, the change to worship on the first day of the week, the age-long observance of Easter and the Lord’s supper, all in addition to the testimonies of the writers of the New Testament, as led and empowered by the Holy Spirit. These all combine to make it certain that Christ died for our sins and rose again for our justification.
1:3 forty days. As Jesus was victorious over His forty-day temptation by Satan (Luke 4:2), so He witnessed to His disciples for forty days of His greater victory over Satan through His death and resurrection (Hebrews 2:14-15).
1:5 baptized with the Holy Ghost. As John had “immersed” (literal meaning of baptizo) the disciples in water, they were shortly to be immersed in the Holy Spirit, in accordance with John’s prophecy (Mark 1:8) and Christ’s promise (John 14:16-17). He would henceforth immerse all future believers into the spiritual body of Christ (I Corinthians 12:13), to indwell them, guide them and be with them always.
1:6 at this time. That the Lord will, at some future time, restore the kingdom to Israel, is clear from the fact that He did not correct this idea (often taught in the Old Testament Scriptures) in the disciples’ understanding. Note, for example, the further confirmation of this teaching in Acts 15:13-18. He did, however, indicate they were not to be concerned about the time of this future kingdom. They had other more immediate responsibilities.
1:7 times or the seasons. This admonition is still appropriate today. No human being, no angel—not even Jesus in the limitations of His human incarnation—can know the date of His return to set up His kingdom (e.g., Mark 13:32).
1:8 power. The “power” associated with the coming of the Holy Spirit on a believer is more than just a dynamic preaching style. It will also involve “boldness” and “great grace” (Acts 4:31,33) in witnessing, centered in the wisdom of God rather than the wisdom of men (I Corinthians 2:4-6) and manifestation of “the fruit of the Spirit” in one’s life (see notes on Galatians 5:22-23).
1:8 Samaria. In a sense this also provides an outline of the book of Acts. Acts 1–7 describe the witness in Jerusalem, Acts 8–12 in Judaea and Samaria, Acts 13–28 in the “uttermost parts of the earth;” the account suspended at the point when Paul had reached the distant capital of the Roman Empire. The narrative focuses mainly on the ministries of Peter and Paul, but the others scattered into various other regions (Acts 8:4). Traditions tell of Thomas going to India, for example, and of others preaching in various distant lands. In any case, the principle still stands. The Christian witness is vital both at home and abroad.
1:10 he went up. Jesus “went up” (as Elijah had long ago—II Kings 2:11) in His physical body, ascending into heaven, where He then “sat on the right hand of God” (Mark 16:19). Thus heaven must be a real place in this physical universe created by God, not some ethereal dimension of time and space entered through a black hole or something of the sort.
1:10 two men. These “two men” witnessing the ascension may well have been the same “two men” at the empty tomb, and even the “two witnesses” who will prophesy in the last days (Revelation 11:3). See discussion on Luke 24:4.