Albert Barnes' Notes on the Whole Bible - Psalms 140:8
Grant not, O Lord, the desires of the wicked - That is, in the matter under consideration. Let them not accomplish their desire in my destruction. Let them not succeed in their designs against me. The prayer, however, “may” be used more generally. It is proper to pray that the desires of the wicked, as wicked people, may not be granted to them; that they may “not” be successful in their purposes. Success in such desires would be only an injury to themselves and to the world. It is proper to... read more
The Pulpit Commentary - Psalms 140:9
As for the head of those that compass me about . The "head" of David's enemies is put in contrast with his own "head" (see Psalms 140:7 ). While God shields and protects his head, theirs has no protection, but the mischief of their own lips which covers them , but with confusion, rather than with defense or safety. read more