Calvin's Commentaries, Vol. 10: Psalms, Part III, tr. by John King, [1847-50], at DarkSideOfTheNet.com
This psalm is merely a part of the fortieth, and the inscription, To call to remembrance, is perhaps designed to indicate this; David having taken these five verses out of that other psalm, and accommodated them for being used on some particular occasion. I shall only here repeat the words of the text; and would refer the reader for the interpretation to the proper place.
To the chief musician of David, to call to remembrance.
1. O God! make haste to deliver me: O Jehovah! hasten to my help. 2. Let those who seek my life be ashamed and confounded; let those who desire my hurt be turned backward, and put to confusion 3. Let those who say to me, Aha! aha! perish as a reward of their shame. 4. Let all those who seek thee rejoice and exult in thee: let those who love thy salvation say, Let God be magnified for evermore! 5. As for me, I am poor and needy: O God! hasten to me: thou art my help and my deliverer: O Jehovah! make no delay.