Lay down now, put me in a surety with thee; who is he that will strike hands with me?
Lay down - namely, a pledge or security - i:e., be my surety; do thou attest my innocence, since my friends only mock me (Job 17:2). Both litigating parties had to lay down a sum as security before the trial.
Put me in surety - provide a surety for me in the trial with thee. A presage of the "surety of a better testament (Hebrews 7:22); or "one Mediator between God and man" (see notes Job 16:21).
Strike hands - `Who else, except God Himself; could strike hands with me!; - i:e., be my security (Psalms 119:122, "Be surety for thy servant for good"). The Hebrew strikes the hand of him for whom he goes security (Proverbs 6:1, "If thou be surety for thy friend, if thou hast stricken thy hand with a stranger").