What does Mark 3:18 mean?

Jesus leaves the crowds behind to select twelve men to be His disciples. The inner circle, Peter, James, and John, have already been mentioned. Now Mark lists most of the rest of the crew.

Andrew may have been the first of the apostles to meet Jesus. He had been a disciple of John the Baptist, who had pointed Jesus out (John 1:35–40). Jesus selects Andrew and his brother Simon Peter in Mark 1:16–17, but Andrew does not spend much time in the inner circle.

John 1:43 says that Jesus calls Philip the day after He calls Andrew and Peter. Philip brings Nathanael, telling him that Jesus is the Messiah "of whom Moses in the Law and also the prophets wrote." Nathanael, also called Bartholomew which means "son of Talmai," responds with a proverb: "Can anything good come out of Nazareth?" (John 1:46). Jesus greets him, saying, "Behold, an Israelite indeed, in whom there is no deceit!" (John 1:47). Jesus also tells Nathanael He saw him before Philip called when he was under a fig tree (John 1:48). This immediately changes Nathanael's perspective of Jesus, and he responds, "Rabbi, you are the Son of God! You are the King of Israel!" (John 1: 49).

Mark 2:14 mentions a disciple called Levi. He's believed to be the same as this verse's Matthew, since he is identified as a tax collector as well (Matthew 10:3). As a tax collector, he would have supported, or at least benefitted from, the Roman occupation. It is he who invites Jesus to eat with the "sinners" (Mark 2:15–17).

Thomas is best known as the disciple who misses Jesus' first appearance after the resurrection and needs to be convinced that Jesus really did rise (John 20:24–28). But he should also be known as the disciple who willingly follows Jesus to Jerusalem despite believing they will all die (John 11:16). He is also known as "Didymus," which means "twin."

Not much is known about the second James except he is apparently Matthew's brother. He is neither James the brother of John nor James the half-brother of Jesus. He is called James the younger in Mark 15:40.

Thaddaeus is also called Judas and is identified as the son of James, but we're never told which James (Luke 6:16).

The second Simon is described as a Zealot. At the time Jesus chooses His disciples, the Zealots were not yet a clearly-defined political party, though they were by the time Mark wrote this account. The Zealots combine the religious fervor of the Pharisees with fierce national independence. Whether Simon's zeal is for the Mosaic Law or Jewish independence, his inclusion in the same group as Matthew—a Roman-sympathizing tax collector—is unusual.