For his mercy. — On account of His mercy. The Jews had their covenant to appeal to, and the attributes of God most clearly brought home to them in Christianity was His veracity in fulfilling the promises contained in this covenant. The Gentiles had no such covenant, and their admission to the blessings of Christianity was an act of pure grace and mercy, which they could only thankfully recognise. The Apostle then proceeds to quote from the Old Testament a succession of passages bearing upon this ultimate reception and triumph of the Gentiles.
For this cause.... — Psalms 18, from which this quotation is taken, is assigned by the heading, as most commentators believe, rightly, to David himself, as a review of his past life, and a thanksgiving for his deliverance from his enemies. David is here taken as a type of Christ. He is said to “confess to God among the Gentiles,” inasmuch as He is the head of the Gentile Church, in whose name its praises are offered, and by whom they are presented.
Confess.... — Comp. the Note on Romans 14:11. Here the meaning, “praise,” is more distinctly brought out. The confession or acknowledgment of mercies is itself an act of praise.