Lord of all to thee we raise this our hymn of grateful praise

As a token of His mercy, the Lord commanded the children of Israel, "Take you on the first day the boughs of goodly trees and branches of palm trees . . . rejoice before the Lord your God" during the harvest-time Feast of Tabernacles (Lev. 23:40, Nehemiah 8:14-18). From that time, the tradition of palm leaves and other branches during important processions was part of the ceremony, as well as times of triumph over foes.
Jesus's victorious entry brought, full circle, centuries of symbolic remembrance of God's love.  The true Deliverer had arrived.  Coming for Passover, riding a colt up the hill into the holy city Jerusalem, Jesus fulfilled prophecy in astonishing detail.  To honor His arrival throngs of people laid down palm branches, just as the children of Israel had been instructed from that first Passover.  That day the ancient practice of bearing palm fronds and other branches connected centuries of tradition.