There will I bring forth a horn to David: I have prepared a lamp for my anointed.

“For Joshua was to lead the people into the land of promise, not Moses. Now he called him an "angel," on account of the magnitude of the mighty deeds that he was to achieve (which mighty deeds Joshua the son of Nun did, and you yourselves have read about) and on account of his office of prophet announcing the divine will. Just as the Spirit, speaking in the person of the Father, calls the forerunner of Christ, John, a future "angel," through the prophet: "Behold, I sent my angel before your"—that is, Christ's—"face, who shall prepare your way before you." Nor is it a novel practice to the Holy Spirit to call those "angels" whom God has appointed as ministers of his power. For the same John is called not merely an "angel" of Christ but also a "lamp" shining before Christ. For David predicts, "I have prepared the lamp for my Christ"; and so Christ, coming "to fulfill the prophets," referred to him [John] [when speaking] to the Jews. "He was," he says, "the burning and shining lamp," being the one who not only prepared his ways in the desert" but, by pointing out "the Lamb of God," enlightened the minds of people by his proclaiming, so that they understood him to be that Lamb whom Moses was accustomed to announce as destined to suffer.”

“"I will clothe her priests with salvation, and her saints shall rejoice and sing" [Psalm 132:16]. We are now at the end of the Psalm; attend for a short space, Beloved. "I will clothe her priests with salvation, and her saints shall rejoice and sing." Who is our salvation, save our Christ? What means, therefore, "I will clothe her priests with salvation"? "As many of you as have been baptized into Christ, have put on Christ." [Galatians 3:27] "And her saints shall rejoice and sing." Whence shall they rejoice and sing? Because they have been clothed with salvation: not in themselves. For they have become light, but in the Lord; for they were darkness before. [Ephesians 5:8] Therefore he has added, "There will I raise up the horn of David" [Psalm 132:17]: this will be David's height, that trust be put in Christ. For horn signifies height: and what sort of height? Not carnal. Therefore, while all the bones are wrapped up in flesh, the horn goes beyond the flesh. Spiritual altitude is a horn. But what is spiritual loftiness, save to trust in Christ? Not to say, It is my work, I baptize; but, "He it is who baptizes." [John 1:33] There is the horn of David: and that you may know that there is the horn of David, heed what follows: "I have ordained a lantern for mine Anointed." What is a lantern? You already know the Lord's words concerning John: "He was a burning and a shining light." [John 5:35] And what says John? "He it is who baptizes." Herein therefore shall the saints rejoice, herein the priests shall rejoice: because all that is good in themselves, is not of themselves, but of Him who has the power of baptizing. Fearlessly therefore does every one who has received baptism come unto His temple; because it is not man's, but His who made the horn of David to flourish.”

“There. Literally, “thither,” (Haydock) Illuc, as Christ came from heaven. (Berthier) — Horn. Power and glory. This regards Solomon, and the Messias. Hebrew, “I will make to bud,” &c., alluding to Christ’s miraculous birth, Isaias iv. 2. (Calmet) — Lamp. St. John the Baptist, (John v. 35.; St. Athanasius) or Christ himself, (Luke ii. 32., and Apocalypse xxi. 23.) though it may also be understood of David’s son and successor. (Calmet) — Yet this lamp was too dreadfully extinguished. (Berthier) — Christ protects his Church, which is placed for the instruction of all. (Worthington)”