Overall meaning :
The Almighty says: They travelled on until they came to a city. They asked its people for some food by way of hospitality. However, being vile and mean, its people refused to receive them as their guests. There they found a wall on the point of tumbling down, and so Al-Khadhir set it up straight. Moses said, ‘Had you wished, you could have demanded payment for this.’
‘This is where you and I part company,’ Al-Khadhir said. ‘But first I will give you the interpretation of those acts of mine to which you objected and which you could not bear to watch with patience.’