Albert Barnes Commentary Psalms 17:12

"He is like a lion that is greedy of his prey, And as it were a young lion lurking in secret places." — Psalms 17:12 (ASV)

Like as a lion - Margin: “The likeness of him” (that is, “of every one of them”) is “as a lion that desires to devour.” The meaning is plain. They were like a lion intent on securing his prey. They watched the object narrowly; they were ready to spring upon it.

That is greedy of his prey - “He is craving to tear.” Prof. Alexander. - The Hebrew word rendered “is greedy,” means “to pine, to long after, to desire greatly.” The Hebrew word rendered “of his prey,” is a verb, meaning “to pluck, to tear, to rend in pieces.” The reference is to the lion that desires to seize his victim, and to rend it in pieces to devour it.

And, as it were, a young lion - Hebrew, “And like a young lion.”

Lurking in secret places - Margin, as in Hebrew: “sitting.” The allusion is to the lion crouching, or lying in wait for a favorable opportunity to pounce upon his prey. See the notes at Psalms 10:8-10. There is no special emphasis to be given to the fact that the “lion” is alluded to in one part of this verse, and the “young lion” in the other. It is in accordance with the custom of parallelism in Hebrew poetry where the same idea, with some little variation, is expressed in both parts of the sentence. See the introduction to Job, Section 5.