Moses and al-Khidr
So, they continued until they reached a town and asked its people for food, but they refused hospitality. Then they found a wall about to collapse, and he restored it. Moses said, “You could have asked for payment.”
18:77So they twain journeyed on till, when they came unto the folk of a certain township, they asked its folk for food, but they refused to make them guests. And they found therein a wall upon the point of falling into ruin, and he repaired it. (Moses) said: If thou hadst wished, thou couldst have taken payment for it.