1:20 book of Psalms. The reference is to Psalm 69:25, which contains several other prophetic references to the future sufferings of Messiah (Psalm 69:8-9,21).

1:20 bishoprick. The last clause is a free quote from Psalm 109:8. The word “bishoprick” literally means “overseer” and should be read here as “office.” Judas and his responsibilities needed to be assumed by another qualified disciple.

1:22 baptism of John. This strongly implies that all the other eleven disciples had “companied with us…beginning from the baptism of John” (Acts 1:21-22), and therefore that all the eleven had originally been baptized by John. They had not been rebaptized when they left John to become disciples of Jesus, for “Jesus Himself baptized not, but His disciples” (John 4:2). In effect they already constituted a local church, even though the Holy Spirit had not yet come. The Lord Jesus, of course, had said He would build His church on the basis of Peter’s great confession that Jesus was “the Christ, the Son of the living God” (Matthew 16:16,18), and then shortly after had laid down principles for discipline in a church (Matthew 18:17). John the Baptist had already been preaching the great truth that Jesus was the Christ, the “Son of God” (John 1:26-34), and apparently his own disciples—at least those who left to follow Jesus—believed it. Although these facts seem to militate against the common dispensational teaching that the church began only at Pentecost, there seems no real reason why the 120 disciples (apparently with Peter in charge) should not be regarded as an organized local church before this, doctrinally sound but not yet empowered by the Spirit. The so-called “invisible church,” consisting of all believing Christians, presumably did begin at Pentecost, although there is no explicit Scripture stating this. The first mention of church in the book of Acts is Acts 2:47: “the Lord added to the church daily such as should be saved.” This probably refers to this same local church there at Jerusalem, although it had suddenly grown very large.

1:22 witness with us. Another requirement for being a member of the twelve apostles was that he must have witnessed the resurrected Christ. Note also I Corinthians 9:1.