1 This is a well-known title; and it is not Christ who speaks; but the prophet speaks to Christ, under the form of wishing, foretelling things to come.
2. “The Lord hear You in the day of trouble”. The Lord hear You in the day in which Thou said, “Father glorify Your Son.” “The name of the God of Jacob protect You.” For to You belongs the younger people. Since “the elder shall serve the younger.”
3. “Send You help from the Holy, and from Sion defend You”. Making for You a sanctified Body, the Church, from watching safe, which waits when You shall come from the wedding.
4. “Be mindful of all Your sacrifice”. Make us mindful of all Your injuries and despiteful treatment, which You have borne for us. “And be Your whole burnt offering made fat.” And turn the cross, whereon You were wholly offered up to God, into the joy of the resurrection.
5. “Diapsalma.” The Lord render to You according to Your Heart. The Lord render to You, not according to their heart, who thought by persecution they could destroy You; but according to Your Heart, wherein Thou knew what profit Your passion would have. “And fulfil all Your counsel.” “And fulfil all Your counsel.” not only that whereby Thou laid down Your life for Your friends, that the corrupted grain might rise again to more abundance; but that also whereby “blindness in part has happened unto Israel, that the fullness of the Gentiles might enter in, and so all Israel might be saved.”
6. “We will exult in Your salvation”. We will exult in that death will in no wise hurt You; for so You will also show that it cannot hurt us either. “And in the name of the Lord our God will we be magnified.” And the confession of Your name shall not only not destroy us, but shall even magnify us.
7. “The Lord fulfil all Your petitions.” The Lord fulfil not only the petitions which You made on earth, but those also whereby Thou intercedest for us in heaven. “Now have I known that the Lord has saved his Christ”. Now has it been shown to me in prophecy, that the Lord will raise up His Christ again. “He will hear Him from His holy heaven.” He will hear Him not from earth only, where He prayed to be glorified; but from heaven also, where interceding for us at the Right Hand of the Father, He has from thence shed abroad the Holy Spirit on them that believe in Him. “In strength is the safety of His right hand.” Our strength is in the safety of His favour, when even out of tribulation He gives help, that “when we are weak, then we may be strong.” “For vain is” that “safety of man,” which comes not of His right hand but of His left: for thereby are they lifted up to great pride, whosoever in their sins have secured a temporal safety.
8. “Some in chariots, and some in horses”. Some are drawn away by the ever moving succession of temporal goods; and some are preferred to proud honours, and in them exult: “But we will exult in the name of the Lord our God.” But we, fixing our hope on things eternal, and not seeking our own glory, will exult in the name of the Lord our God.
9. “They have been bound, and fallen”. And therefore were they bound by the lust of temporal things, fearing to spare the Lord, lest they should lose their place by “the Romans:” and rushing violently on the stone of offense and rock of stumbling, they fell from the heavenly hope: to whom the blindness in part of Israel has happened, being ignorant of God's righteousness, and wishing to establish their own. “But we are risen, and stand upright.” But we, that the Gentile people might enter in, out of the stones raised up as children to Abraham, who followed not after righteousness, have attained to it, and are risen; and not by our own strength, but being justified by faith, we stand upright.
10. “O Lord, save the King:” that He, who in His Passion has shown us an example of conflict, should also offer up our sacrifices, the Priest raised from the dead, and established in heaven. “And hear us in the day when we shall call on You”. And as He now offers for us, “hear us in the day when we shall call on You.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)