Ever since Zechariah (14:1-4) prophesied that "a day is coming for the Lord," people have associated the Mt. of Olives with the arrival of the Messiah:

Behold, a day is coming for the LORD when the spoil taken from you will be divided among you. For I will gather all the nations against Jerusalem to battle, and the city will be captured, the houses plundered, the women ravished and half of the city exiled, but the rest of the people will not be cut off from the city. Then the LORD will go forth and fight against those nations, as when He fights on a day of battle. In that day His feet will stand on the Mount of Olives, which is in front of Jerusalem on the east; and the Mount of Olives will be split in its middle from east to west by a very large valley, so that half of the mountain will move toward the north and the other half toward the south.

It was important, therefore, that Jesus, as the Messiah, should approach the city over this mountain. In fulfillment of Zechariah 9:9, he does so riding on a donkey.

Luke 19:29-48

When He approached Bethphage and Bethany, near the mount that is called Olivet, He sent two of the disciples, saying, "Go into the village ahead of you; there, as you enter, you will find a colt tied on which no one yet has ever sat; untie it and bring it here.  If anyone asks you, 'Why are you untying it?' you shall say, 'The Lord has need of it.'" So those who were sent went away and found it just as He had told them. As they were untying the colt, its owners said to them, "Why are you untying the colt?" They said, "The Lord has need of it." They brought it to Jesus, and they threw their coats on the colt and put Jesus on it. As He was going, they were spreading their coats on the road. As soon as He was approaching, near the descent of the Mount of Olives, the whole crowd of the disciples began to praise God joyfully with a loud voice for all the miracles which they had seen, shouting:

     "Blessed is the King who comes in the name of the Lord;

     Peace in heaven and glory in the highest!"

Some of the Pharisees in the crowd said to Him, "Teacher, rebuke Your disciples." But Jesus answered, "I tell you, if these become silent, the stones will cry out!"

When He approached Jerusalem, He saw the city and wept over it, saying, "If you had known in this day, even you, the things which make for peace! But now they have been hidden from your eyes. For the days will come upon you when your enemies will throw up a barricade against you, and surround you and hem you in on every side, and they will level you to the ground and your children within you, and they will not leave in you one stone upon another, because you did not recognize the time of your visitation."

Jesus entered the temple and began to drive out those who were selling, saying to them, "It is written, 'And My house shall be a house of prayer,' but you have made it a robbers' den."

And He was teaching daily in the temple; but the chief priests and the scribes and the leading men among the people were trying to destroy Him, and they could not find anything that they might do, for all the people were hanging on to every word He said.