Verses 171-172 both express the psalmist’s promise to praise Yahweh because of his statutes and because his commandments are right. My lips in verse 171 and My tongue in verse 172 are figures of speech for the psalmist himself. For teach me thy statutes in verse 171b, see verses 64b, 68b, 124b. For all thy commandments are right in verse 172b, see similar expressions in verses 137b, 144a, and especially in verse 151b.

In verse 173 the psalmist again appeals to Yahweh for help; in this verse thy hand is also a figure of speech, denoting Yahweh himself. In verse 173b I have chosen describes a deliberate decision by the psalmist to obey Yahweh’s laws.

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 .