Some argue that the Bible is contradictory concerning the lists of disciples, since they are different. The argument is that Matthew 10:2-4, Mark 3:13-19, Luke 6:12-16, and Acts 1:13-14 present different lists of disciples. However, the solution to this alleged contradiction in the Bible is simple.
The names of the twelve apostles are these: first, Simon, who is called Peter, and Andrew his brother; James the son of Zebedee, and John his brother; 3 Philip and Bartholomew; Thomas and Matthew the tax collector; James the son of Alphaeus, and Thaddaeus; 4 Simon the Zealot, and Judas Iscariot, who betrayed him. Matthew 10:2-4
13 And he went up on the mountain and called to him those whom he desired, and they came to him. 14 And he appointed twelve (whom he also named apostles) so that they might be with him and he might send them out to preach 15 and have authority to cast out demons. 16 He appointed the twelve: Simon (to whom he gave the name Peter); 17 James the son of Zebedee and John the brother of James (to whom he gave the name Boanerges, that is, Sons of Thunder); 18 Andrew, and Philip, and Bartholomew, and Matthew, and Thomas, and James the son of Alphaeus, and Thaddaeus, and Simon the Zealot,[a] 19 and Judas Iscariot, who betrayed him. Mark 3:13-19
12 In these days he went out to the mountain to pray, and all night he continued in prayer to God. 13 And when day came, he called his disciples and chose from them twelve, whom he named apostles: 14 Simon, whom he named Peter, and Andrew his brother, and James and John, and Philip, and Bartholomew, 15 and Matthew, and Thomas, and James the son of Alphaeus, and Simon who was called the Zealot, 16 and Judas the son of James, and Judas Iscariot, who became a traitor. Luke 6:12-16
13 And when they had entered, they went up to the upper room, where they were staying, Peter and John and James and Andrew, Philip and Thomas, Bartholomew and Matthew, James the son of Alphaeus and Simon the Zealot and Judas the son of James. 14 All these with one accord were devoting themselves to prayer, together with the women and Mary the mother of Jesus, and his brothers. Acts 1:13-14
| Matthew 10:2-4 | Mark 3:13-19 | Luke 6:12-16 | Acts 1:13-14 |
| Simon (Peter) | Simon (Peter) | Simon (Peter) | Peter |
| James, son of Zebedee | James, son of Zebedee | James | James |
| John, the brother of James | John, the brother of James | John | John |
| Andrew | Andrew | Andrew | Andrew |
| Philip | Philip | Philip | Philip |
| Bartholomew | Bartholomew | Bartholomew | Bartholomew |
| Matthew | Matthew | Matthew | Matthew |
| Thomas | Thomas | Thomas | Thomas |
| James, son of Alphaeus | James, son of Alphaeus | James, son of Alphaeus | James, son of Alphaeus |
| Thaddaeus | Thaddaeus | ||
| Simon the Zealot | Simon the Zealot | Simon the Zealot | Simon the Zealot |
| Judas Iscariot | Judas Iscariot | Judas Iscariot | |
| Judas the son of James | Judas the son of James | ||
| Matthias |
The most likely explanation for why the lists of disciples are different is that Thaddaeus and Judas the son of James are the same person. Perhaps Judas the son of James did not want to be called Judas because Judas was the name of the man who betrayed Jesus.
There are other examples of one person having two different names (for example, Simon/Peter and Matthew/Levi), so this makes complete sense.
The reason why Acts includes Matthias is that Matthias was chosen to replace Judas Iscariot.
To read more answers to alleged and apparent contradictions in the Bible, see “Contradictions” in the Bible Answered.
These books are also excellent resources:
Evidence That Demands a Verdict: Life-Changing Truth for a Skeptical World - Josh and Sean McDowell
Little Pilgrim's Progress (Illustrated Edition) - Helen L. Taylor