For verse 6 see similar language in 28.2; 55.1.
For verse 7a see 50.15a; 77.2a.
Quoted with permission from Bratcher, Robert G. and Reyburn, William D. A Handbook on the Book of Psalms. (UBS Helps for Translators). New York: UBS, 1991. For this and other handbooks for translators see here .