Augustine of Hippo — as excerpted in the Catena Aurea on John 12:12-19

“(Tr. li. 1) See how great was the fruit of His preaching, and how large a flock of the lost sheep of the house of Israel heard the voice of their Shepherd: On the next day much people that were come to the feast, when they heard that Jesus was coming to Jerusalem, took branches of palm trees. The branches of palms are songs of praise, for the victory which our Lord was about to obtain by His death over death, and His triumph over the devil, the prince of death, by the trophy of the cross.”