Though Solomon had commended friendship in adversity (Pro 17:17), yet let not any, under pretence of being generous to their friends, be unjust to their families and wrong them; one part of our duty must be made to consist with another. Note, 1. It is a piece of wisdom to keep out of debt as much as may be, especially to dread suretiship. There may be a just occasion for a man to pass his word for his friend in his absence, till he come to engage himself; but to be surety in the presence of his friend, when he is upon the spot, supposes that his own word will not be taken, he being deemed insolvent or dishonest, and then who can with safety pass his word for him? 2. Those that are void of understanding are commonly taken in this snare, to the prejudice of their families, and therefore ought not to be trusted too far with their own affairs, but to be under direction.

A man void of understanding striketh hands,.... With his friend's creditor, and becomes surety for him; and thereby acts a very unwise part, and shows himself to want understanding, by taking such a step, which may prove the ruin of himself and family: for though a man may and should love his friend at all times; yet he is not obliged, under a notion of friendship, to injure himself and his family, or to run the risk of it; if he does, it is a plain case he wants wisdom and discretion, see Pro 6:1;

and becometh surety in the presence of his friend; not the creditor, but the debtor; and to pass his word for him, when he is present, shows that his own word will not be taken; and that he is either thought to be in bad circumstances, and incapable of payment at the proper time; or else that he is a bad man, of dishonest principles, and will not; and in either case it is not advisable to become surety for such a man: and besides, doing it in his presence may make him more careless and unconcerned about making good his payment or contract at the appointed time, when he knows his friend is engaged him.

(Compare Pro 6:1-5; Pro 11:15).

in the presence, &c.--that is, he either fails to consult his friend, or to follow his advice.