that say... good. See note on Psalms 144:12-15.
lift Thou up. No priest with David to give the blessing of Numbers 6:24-26. See 2 Samuel 15:32-37.
countenance. Figure of speech Anthropopatheia.
Related Commentaries of Psalms 4:6
Psalms 4:6
6 There be many that say, Who will shew us any good? LORD, lift thou up the light of thy countenance upon us.