"He who puts up security for another man will surely suffer . . ." (Proverbs 11:15).
What? Are we really being advised to look out for our own interests above all? No. What we learn is the wisdom that life--including our economic fortunes--are not dependable. They cannot be trusted upon to reward us. This because human beings themselves are not perfectly reliable. Sometimes they let us down. What we have here is an observation about the human condition--not a moral law. We do well to heed it.