'Coals' in the Bible

Now the servants and the officers had made a fire of coals, because it was cold, and they were standing and warming themselves. And Peter was with them, standing and warming himself.

So when they got out on the beach, they saw a charcoal fire set up and fish on it cooking, and bread.

But if your enemy is hungry, feed him; if he is thirsty, give him a drink; for by doing this you will heap burning coals on his head.”