Church Fathers on John 12:19

The Law enjoined, that on the tenth day of the first month a lamb or a kid should be shut up in the house, and be kept to the fourteenth day of the same month, on the evening of which day it was sacrificed. In accordance with this law, the Elect Lamb, the Lamb without spot, when He went up to Jerusalem to be immolated for the sanctification of the people, went up five days before, i.e. on the tenth day.

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.

It is a compound of two words; Hosi is shortened into save; Anna a mere exclamation, complete. Blessed is He that comes in the name of the Lord. The name of the Lord here is the name of God the Father; though we may understand it as His own name; inasmuch as He also is the Lord. But the former sense agrees better with the text above, I am come in My Father’s name. He does not lose His divinity, when He teaches us humility.