What does Matthew 21:2 mean?
Jesus and His disciples have been travelling from Galilee to Jerusalem and are now about a mile away. Jesus is sending two of the disciples into a nearby village. He tells them they will find a donkey that is tied up and waiting for them, along with its young colt. They are to untie the animals and bring them to Jesus. Mark's account mentions that the disciples will bring the animal back (Mark 11:3). Some suggest the donkey's owner might have been there to see Jesus' resurrection of Lazarus in Bethany (John 11:44–45), which happened the day before (John 12:12–13), and was anticipating the request.However it happened, Matthew is indicating that Jesus has prearranged to have these animals waiting for Him. He specifically intends to ride them into Jerusalem as He arrives there. At least one reason for this is to intentionally fulfill a Messianic prophecy from Zechariah (Zechariah 9:9) that Matthew will reference later (Matthew 21:5). Commentators describe this as an "acted parable" in which Jesus is revealing His identity as the Messiah.
The imagery of a donkey is important, since they are only suitable for work, not for war. A conquering general might enter town on a horse, but Messiah's first public proclamation will not be associated with conquest.