Jesus arrived in Judea before Passover week began and supped in Bethany with His friends. Word spread quickly that He was in the area and large groups of people began to assemble. John tells us that they came not only because of Jesus but to see Lazarus, the man who had been dead and buried but raised from the tomb. Despite whether they came to see Lazarus or Jesus, once they had seen Jesus many went away believing in Him, and marveling at the things He had done. This irritated the Chief Priests so much they counseled together how they might put both Jesus and Lazarus to death and put a end to all this talk of miracles and messiahs.
The disciples did as Jesus commanded and everything happened exactly as He told them it would.
The interesting thing about this account is that Jesus knew exactly where the colt would be found and even the words that would be spoken. Looking back on this experience after the crucifixion, the disciples could not help but understand that this was part of the plan that would bring about His death. He knew, when He asked them to go for the colt, what lay ahead for Him.
But there is more to learn from this account. An ass had specific symbolism that is important here. Horses were used by soldiers for warfare, but an ass or a mule were gentler animals and thus symbols of royalty. While history often shows us kings who are selfish and proud, the intent has always been that a king should be someone who loves, protects, and cares for his people. Thus by His choice to ride an ass, Jesus proclaims to all who have eyes to see that He has come not as a warrior who will save them from Roman bondage, but as a King who will save them from the bondage of sin. And just as the colt had never been ridden before, this type of King had never been known before.