Some argue that the Bible is contradictory concerning when Peter and Andrew started following Jesus. The argument is that Matthew 4:18-19 says that Peter and Andrew started following Jesus when they were fishing in the Sea of Galilee, but John 1:42-43 says that they started following Jesus somewhere else. However, there is a very simple explanation to this alleged contradiction in the Bible.
While walking by the Sea of Galilee, he saw two brothers, Simon (who is called Peter) and Andrew his brother, casting a net into the sea, for they were fishermen. 19 And he said to them, “Follow me, and I will make you fishers of men.” 20 Immediately they left their nets and followed him. Matthew 4:18-20
35 The next day again John was standing with two of his disciples, 36 and he looked at Jesus as he walked by and said, “Behold, the Lamb of God!” 37 The two disciples heard him say this, and they followed Jesus. 38 Jesus turned and saw them following and said to them, “What are you seeking?” And they said to him, “Rabbi” (which means Teacher), “where are you staying?” 39 He said to them, “Come and you will see.” So they came and saw where he was staying, and they stayed with him that day, for it was about the tenth hour. 40 One of the two who heard John speak and followed Jesus was Andrew, Simon Peter’s brother. 41 He first found his own brother Simon and said to him, “We have found the Messiah” (which means Christ). 42 He brought him to Jesus. Jesus looked at him and said, “You are Simon the son of John. You shall be called Cephas” (which means Peter). John 1:35-42
Matthew 4:18-20 and John 1:42-43 present two different meetings between Jesus and the brothers. In John 1:42-43, Jesus meets Peter and Andrew for the first time, and they start following Jesus because Jesus is a respected teacher. In Matthew 4:18-20, Jesus explicitly calls Peter and Andrew to follow him in a special way, saying that he will make them “fishers of men,” and they obey.
The two passages are not mutually exclusive, and there is simply no contradiction between them.
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