Knoweth — i.e., recogniseth with discriminative discernment and appreciation. (Comp. Psalms 31:7; Psalms 144:3; Exodus 2:25; also John 10:14. So Shakespeare, As You Like It: “I know you are my eldest brother, and in the gentle condition of blood you should so know me.”)
The way of the ungodly shall perish. — This is explained by Psalms 112:10, “the desire of the wicked shall perish;” all his plans and ambitions shall come to nought. The metaphor is illustrated by Job 6:18, where an unjust course is compared to a stream that suddenly dries up and disappears.