Proverbs 17:18 A man void of understanding strikes hands, and becomes surety in the presence of his friend. 

‘A man void of understanding strikes hands, and becomes surety in the presence of his friend.’ This means: A man who lacks wisdom and discernment is quick to shake hands on a deal, that is, to seal an agreement or contract, without carefully considering the consequences. By becoming surety, he pledges himself as a guarantor for another person’s debt or obligation, often doing so impulsively and in the presence of a friend.

Such a person exposes his lack of understanding by committing himself financially or legally on behalf of someone else without proper thought. Even if the friend is trustworthy, the act of hastily entering into such a risky obligation without due diligence is foolish.

In essence, this verse warns against rash promises and unwise financial entanglements. It teaches that true understanding involves prudence, restraint, and a careful weighing of consequences, especially when it comes to matters of trust and liability.

Proverbs 11:15 He that is surety for a stranger shall smart for it: and he that hates suretiship is sure. 

‘Surety’ – Pledging to stand good for anyone tends to relieve the borrower of the responsibility he should feel, and often lowers the respect of a co-signer in the sight of the one he helps.

Five facts about surety: The command against surety (22:26). The command to get out of surety as quickly as possible (6:1-5). Surety is a sign of a lack of understanding (17:18). Suffering and disappointment are what is promised in surety (11:15). To refrain from surety is the only safe way (11:15).

A man who quickly concludes a contract and becomes surety in the presence of a friend proves he is void of understanding (17:18). Do not be quick to shake hands (make contracts and give promises) or co-sign for the debts of others. If you have nothing to pay, why lose the necessities of life by pledging them as security (22:26-27)?

Proverbs 6:1-5 My son, if thou be surety for thy friend, if thou have stricken thy hand with a stranger, Thou are snared with the words of thy mouth, thou are taken with the words of thy mouth. Do this now, my son, and deliver thyself, when thou are come into the hand of thy friend; go, humble thyself, and make sure thy friend. Give not sleep to thine eyes, nor slumber to thine eyelids. Deliver thyself as a roe from the hand of the hunter, and as a bird from the hand of the fowler. 

‘Surety for thy friend.’ Pledging to stand good for anyone tends to relieve the borrower of the responsibility he should feel, and often lowers the respect of a co-signer in the sight of the one he helps. Five facts about surety: The command against surety (22:26). The command to get out of surety as quickly as possible (6:1-5). Surety is a sign of lack of understanding (17:18). Suffering and disappointment are what is promised in surety (11:15). To refrain from surety is the only safe way (11:15).

‘Stricken thy hand.’ Shaking hands was considered the ratification of a verbal contract or promise, and thus a man became ensnared with the words of his mouth (6:1-2; cp. Job 17:3).

‘Do this now, my son, and deliver thyself, when thou are come into the hand of thy friend.’ Continue to press the one you are surety for to pay his debt, or you will be left to pay it. If you are ensnared and obligated, make every effort, as the antelope taken in a net or a bird in a snare, to free yourself from captivity (6:3-5).