Shall deliver them - that is, the righteous themselves.

The words of the wicked are to lie in wait for blood — that is, are calculated for this end.

The mouth…

The words of the wicked [are] to lie in wait for blood
Which some understand of perjury and false witness, as Jarchi…

Wicked people speak mischief to their neighbors. A man may sometimes do a good work with one good word.