A man void of understanding (Hebrew, heart) striketh hands; clinches the bargain which makes him responsible (see on suretyship, Proverbs 6:1, etc.; and note, Proverbs 20:16). Becometh surety in the presence of his friend; to his friend for some third party.
What is here censured is the weakness which, for the sake of perhaps worthless companions, lets itself be hampered and endangered by others' obligations. For, as our adage runs, he that is surety for another is never sure himself.
The Septuagint takes the "striking of hands" to be a sign of joy (Vulgate, plaudet manibus), "The foolish man claps ( ἐπικροτεῖ) and rejoices in himself, so also he who pledges himself for his friend."