kesel

This is a body word before it is anything else. It names the soft place low on the back where the flesh is thickest, right next to the kidneys. Priests and butchers knew the spot exactly, because it is where the hard fat lies that Israel's law reserved for the altar.

Five of the thirteen uses are the same sentence, repeated as a standing instruction in Leviticus: take the two kidneys, and the fat that is on them, which is by the loins. That wording is a recipe rather than a picture. It tells whoever is cutting up the animal precisely which piece of fat to lift out.

Away from the altar, the same spot shows up on people. Job describes a rich man who has grown a roll of fat over his flank, a picture of soft and careless prosperity. A psalmist says his loins are filled with burning, which is what an ache in the small of the back feels like from the inside. The ordinary Hebrew word for the waist (מׇתְנַיִם) covers the whole midsection and is where a belt goes; this word points at a smaller, meatier target.

Confidence here is not a mood. It is the prop itself, the thing taking the weight. So the word can be pointed at gold, at a house, or at God, and the question the text asks is always the same one: will it hold?

Job swears he never made gold his confidence, and sets the word beside another for trust (מִבְטָח) in the very next line. Bildad says the godless man's confidence is a spider's web, which is his whole argument in one image: the thread is real, it is simply far too thin to bear anything. Read against that, Proverbs is making a promise rather than a pleasantry when it says the LORD himself will be your confidence.

Hebrew also has a forward-looking word for hope, תִּקְוָה, which is about what a person expects to happen. This word is about what a person leans on. English Bibles translate both with "hope" and "confidence" and often swap them freely, but the two words are asking different questions.

This is stupidity as thickness, not as a lack of schooling. The picture underneath it is dullness: someone too well padded, too comfortable, too slow to take anything in. Hebrew has several words for a fool, and this one belongs with the thick-headed fool of Proverbs (כְּסִיל), the man who is not so much uninformed as unteachable.

Ecclesiastes drops it into a short list of things the Teacher set out to understand: wickedness, this thick folly, and the foolishness (סִכְלוּת) that runs on into madness. The word is not naming a slip in judgment. It names a way of living.

Scholars are not agreed that this is a separate meaning at all. It may be the confidence sense said with a sneer, since what a person counts on, when the thing counted on is worthless, is exactly their stupidity. Both readings are alive, and two verses are the whole of the evidence.