On Palm Sunday, Christians celebrate the Triumphal Entry of Jesus Christ into Jerusalem, one week before his execution by crucifixion. The Bible reveals that when Jesus entered Jerusalem, he rode a donkey and the crowds greeted him with waving palm branches, at the same time covering his path with palm branches. The people shouted, "Hosanna! Blessed is the one who comes in the name of the Lord – the King of Israel!".
The earliest evidence of Palm Sunday events can be traced back to Jerusalem in the 4th century, according to Peregrinatio Egeriae, the travel diary of a woman who had traveled to Jerusalem and observed the festivities  including the key ritual of a procession with palm fronds. The celebration of Palm Sunday doesn’t appear to have caught on in the West until some time around the 8th century, based upon Gobbio Missal, a Gallican sacramentary.
In the Middle Ages, the process and blessing of the palm fronds was very elaborate, involving a great deal of singing, chanting, and processions that went from one local church to another. Later the ceremonies became simplified in order to focus more on the death and suffering of Jesus and the central part of the day involves a reading from one of the passion stories in the gospels – thus the name Passion Sunday.
When we attend Mass, we notice that the priests and deacons are wearing red vestments. The congregation is also invited to wear red. When Mass begins, the priest blesses palms, and there is a reading of the account when Jesus entered Jerusalem.
What we remember most about Palm Sunday is that we brought palm fronds to be blessed by the priest and after it was blessed, we hanged them on a prominent part of the house where they stayed till the next year’s Palm Sunday. The blessed palms are part and parcel of most Filipino households. Most people know that the palm fronds that were blessed are also the source of ashes used on Ash Wednesday to mark the foreheads of the faithful. It is a blessed reminder of the saying "Dust thou art and to dust returneth". That, of course, only refers to our physical being and not our spiritual selves. In many parts of the world, people greet each other by saying, "I bow to the spirit that resides within you" and the other person’s answer is, "And I bow to the spirit that resides within you that is part of the cosmic universe". Thus, we don’t return to dust, we go into another dimension.