What does Proverbs 6:1 mean?

Under the Old Testament, a person was permitted to lend money to a fellow Israelite as a way of helping him out of distress. However, in those cases, the lender was not supposed to attach an interest rate to the loan. Exodus 22:25 states specifically: "If you lend money to any of my people with you who is poor, you shall not be like a moneylender to him, and you shall not exact interest from him." Further, verse 26 commands: "If ever you take your neighbor's cloak in pledge, you shall return it to him before the sun goes down." Returning the cloak before sundown would provide protection against the temperature drop—it was an article of clothing the person needed. Leviticus 25:35–37 also prohibited an Israelite from charging interest or making a profit from a loan to a fellow Israelite.

The phrase "put up security," also translated as "become surety" means to become a cosigner for someone else's loan. The warning here does not seem to be against all borrowing, of all kinds. Rather, the danger is in tying one's own finances to another person's reliability. If the borrower is not faithful, the person who "put up security" for them risks losing their own wealth.