How people foolishly make idols.
He heweth him down cedars, and taketh the cypress and the oak, which he strengtheneth for himself among the trees of the forest; he planteth an ash, and rain doth nourish it.
Then shall it be for a man to burn: for he will take thereof, and warm himself; yea, he kindleth it, and baketh bread; yea, he maketh a god, and worshippeth it; he maketh it a graven image, and falleth down thereto.
He burneth part thereof in the fire; with part thereof he eateth flesh; he roasteth roast, and is satisfied: yea, he warmeth himself, and saith, Aha, I am warm, I have seen the fire:
And the residue thereof he maketh a god, even his graven image: he falleth down unto it, and worshippeth it, and prayeth unto it, and saith, Deliver me; for thou art my god.
Human plant trees like the cypress, the heavens water it, humans receive the goodness of heat, cooking food with it, and then with the leftover wood turns around and makes an idol and worships it, expecting the scraps to have "magic" power, a god, to "deliver" him. As line 20 says "He feedeth on ashes: a deceived heart hath turned him aside."