Commentaries:
Barnes' Notes
O Lord God, to whom vengeance belongeth ... - Margin, God of revenges The idea is, that it pertains to God to take vengeance, or to punish for crimes. See the notes at Romans 12:19. The appeal here is made to God in view of the crimes committed by others, and which are referred to in the subsequent part of the psalm. God is addressed as having the right to restrain and punish wicked people, and he is asked to interpose and assert that right in a case which clearly demanded it. The appeal is repeated to make it emphatic, or to denote "earnestness" in the petition.
Show thyself - Margin, as in Hebrew, "shine forth." The meaning is, Manifest thyself; come forth as such a God; Proverbs thy right; display thy power, and show that thou art a God opposed to crime and wrong. The same Hebrew word is used here which is found in Psalms 80:1, and which is there rendered "shine forth." See the notes at that passage.
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