Matthew was an eyewitness of Jesus writing his account of his experience with Jesus to help people discover that the Jesus is the promised Messiah.
Jesus fulfilled the prophecies about the Messiah which are mathematically improbable!
We have copies of the Hebrew Scriptures that pre-date the life of Jesus so these fulfilled prophecies were not written up after Jesus' life. Many of these prophecies are things that happened to the Messiah not things He could control.
