13 “Bless our God, you nations”. Behold, there have been driven back they that are bitter, reckoning has been made with them: some have been converted, some have continued proud. Let not them terrify you that grudge the Gentiles Gospel Grace: now has come the Seed of Abraham, in whom are blessed all nations. Bless ye Him in whom you are blessed, “Bless our God, you nations: and hear ye the voice of His praise.” Praise not yourselves, but praise Him. What is the voice of His praise?
That by His Grace we are whatever of good we are. “Who has set my Soul unto life” Behold the voice of his praise: “Who has set my Soul unto life.” Therefore in death she was: in death she was, in yourself. Thence it is that you ought not to have been exalted in yourselves. Therefore in death she was, in yourself: where will it be in life, save in Him that said, “I am the Way, the Truth, and the Life”? Just as to certain believers the Apostle says, “You were sometime darkness, but now light in the Lord.”...“And has not given unto motion my feet.” He has set my Soul unto life, He guides the feet that they stumble not, be not moved and given unto motion; He makes us to live, He makes us to persevere even unto the end, in order that for everlasting we may live....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)