Palm Branches For The Advent of Their King

12 The next day the large crowd that had come to the feast heard that Jesus was coming to Jerusalem. 13 So they took branches of palm trees and went out to meet him, crying out, “Hosanna! Blessed is he who comes in the name of the Lord, even the King of Israel!” 14 And Jesus found a young donkey and sat on it, just as it is written,

15 “Fear not, daughter of Zion;
behold, your king is coming,
sitting on a donkey's colt!”
16 His disciples did not understand these things at first, but when Jesus was glorified, then they remembered that these things had been written about him and had been done to him. 17 The crowd that had been with him when he called Lazarus out of the tomb and raised him from the dead continued to bear witness. 18 The reason why the crowd went to meet him was that they heard he had done this sign. 19 So the Pharisees said to one another, “You see that you are gaining nothing. Look, the world has gone after him.” (John 12: 12-19)
So the took branches of Palm trees. Palm branches had deep symbolic meaning for Israel in Jesus day. They were symbols of the Maccabean revolt, because the Maccabees used them to celebrate their victory, they even had them printed on their coins from that period. John doesn’t mention coats. Only the palm branches. The people were greeting their king. In this the people were right, but they had no idea what it all meant.
The disciples themselves, John tells us were not aware. Only after Jesus was raised from the dead, only after he had been glorified did any of this make sense. There were prophecies hidden in scripture that no one took as prophecies of the messiah. But when Jesus was raised from the dead, then the disciples read the scriptures in new light, the Old Testament in new light and began to understand that this book was completely about Jesus. It still is.
The New Testament that we have, the books of the New Testament I should say, they are the books of the New Testament because they testify to the New Testament in His Blood, just as the books of the Old Testament testify to Abraham’s bloody testament that was finally fulfilled when Jesus first shed his blood for you, not on the cross but in circumcision. (8 days old, he didn’t have a “choice” but he did it and it was effective for you, same as baptism effective for you despite any choice you may or may not have had. But let’s be honest even if you thought you were making a choice, it wasn’t really a choice.)
The Books of the New Testament, the early church understood them to be basic commentary on the Old Testament, commentary in light of Jesus death and resurrection. This makes reading the Old Testament fun, it becomes a game to find Christ in there, but that isn’t too hard of a game when you understand what Christ has done. He’s all over the place in the Old Testament, and not in such a manner as you find some people trying to read Proverbs and correlate them to Jesus’ Sermon on the Mount or some such nonsense, but in that the central event of Christ’s life and our life in Christ, his death and resurrection permeate the entire Old Testament and lead up to this day when Israel greets the advent of her king with palm branches as he rides in on a donkey. No, they didn’t realize the full import of it, but it was true nonetheless.