What does Acts 1:23 mean?

The group of 120 Jesus-followers praying in an upper room in Jerusalem (Acts 1:12–15) look over their number and find two who are qualified to replace Judas Iscariot as an apostle. Only two others were with Jesus during His baptism, traveled with Him and the disciples during His ministry, and saw Him after the resurrection (Acts 1:21–22).

These specific requirements disqualified a lot of good men and women. James, Jesus' brother, did not follow Jesus' ministry and only came to believe He was the Messiah after the resurrection (1 Corinthians 15:7). But James becomes the leader of the church in Jerusalem. It's possible Stephen and Philip are there. Both of these men will be chosen in the first group of deacons (Acts 6:1–7). Stephen will have a significant role as the first martyr (Acts 7), and Philip will be a powerful evangelist (Acts 8:4–40). Several women are there, as well—women who had important roles in Jesus' ministry. But being one of the twelve apostles is not their role in the church.

Not much is known about the two men who are nominated. "Barsabbas" is Aramaic and means "son of God's will" or "son of Sabbath." It may be a nickname, meaning he devoutly follows the Sabbath. Joseph is his proper name, but like many at that time, he also has a Roman name, Justus. Eusebius says Matthias was one of the Seventy (Luke 10:1–12, 17–20). When the group in the upper room casts lots, Matthias is chosen (Acts 1:26).