O Lord, save us now;
O Lord, prosper us now.
Blessed is he who comes in the name of the Lord;
We blessed you from the house of the Lord.
God is the Lord, and He revealed Himself to us;
Appoint a feast for yourselves, decked with branches,
Even to the horns of the altar.
You are my God, and I will give thanks to You;
You are my God, and I shall exalt You;
I will give thanks to You, for You heard me;
And You became my salvation.
Give thanks to the Lord, for He is good;
For His mercy endures forever. (Psalm 118:25-29 LXX)
The next day a great multitude that had come to the feast, when they heard that Jesus was coming to Jerusalem, took branches of palm trees and went out to meet Him, and cried out: “Hosanna! ‘Blessed is He who comes in the name of the Lord!’ The King of Israel!” Then Jesus, when He had found a young donkey, sat on it; as it is written: “Fear not, daughter of Zion; Behold, your King is coming, Sitting on a donkey’s colt.” (John 12:12–15)
“In the name of the Lord” signifies “in the name of God the Father,” just as Himself said elsewhere to the unbelieving Jews, “I have come in the name of my Father, and you do not receive me; another will come in his own name, him you will receive.” Christ came in the name of God the Father, because in everything that he did and said he was concerned with glorifying his Father and with proclaiming to human beings that he is to be glorified. The antichrist will come in his own name, and although he may be the most wicked person of all and a convivial companion of the devil, he will see fit to call himself the Son of God while “being opposed to and raised above everything that is said to be God and is worshiped.” The crowd took this verse of praise from Ps 117 [LXX], and there is no one who doubts that it is sung about the Lord. Hence it is appropriate that there is previously sung of him in the same psalm, “The stone that the builders rejected has become the cornerstone.” For Christ, whom the Jews rejected as they were building the decrees of their own traditions, became a memorial for believers from among both peoples, namely, the Jews and the Gentiles. For as to the fact that Christ is called the cornerstone in this psalm, this is what was being chanted in high praise in the gospel by the voice of those who followed and those who went ahead.
Bede, Homilies on the Gospels 2.3
Blessed is the one who comes in the name of the Lord. The children also offered this cry to the Lord as an accusation against those who professed to teach the divine sayings but were unwilling to understand their true meaning. Since the Scribes and Pharisees called the Lord a Samaritan, the children called him the one who is coming and blessed; and the term Hosanna likewise occurs in the prophecy, as we find the phrase Please save occurring as Hosanna in the Hebrew. Hence blessed John the Baptist, to guide his own disciples to the truth, asked the Lord through them, “Are you the one who is to come, or should we wait for someone else?” Being Lord, he has come in the name of the Lord; thus he said to Jews, “I have come in my Father’s name, and you did not receive me; another comes in his own name, and him you will receive.” And being blessed, he is son of the Blessed One; thus the high priest also asked, “Are you the son of the Blessed One?” We blessed you from the house of the Lord. The victors say this to their friends, We offer you the blessing of this stone, which became a house for God the Word in it: “The Word was made flesh,” Scripture says, “and dwelt among us”; and the Lord said to Jews, “Destroy this temple, and in three days I shall raise it up.”
The Lord is God, and he has appeared to us. Here he has clearly declared the divinity of Christ the Lord: the one he called stone above and later blessed and coming in the name of the Lord he named Lord and God, who made his particular appearance and regaled the believers with salvation. Observe a festival with the garlands as far as the horns of the altar: assemble, therefore, all, and conduct a very great festal assembly in celebration of your own salvation so that a massed gathering arrives at the very altar.
Theodoret of Cyrus, Commentary on Psalm 118.11–12