Tafsir of Al-Kahf 18:79

{For the poor} It is said they were ten brothers: five of them were disabled, and five worked at sea.

{Behind them} Meaning: in front of them. Just as the Almighty said: {And behind them is a barrier} (Al-Mu'minun: 100). It is also said: [literally] behind them, for their path upon returning would pass by him, and they had no knowledge of it, so Allah informed Al-Khidr of it. The king’s name was Julundi.

If you ask: His saying {So I intended to cause a defect in it} is a consequence of the fear of it being seized by force, so it should logically follow the cause; why then was it placed before it?

I say: The intention is for it to be delayed, but it was brought forward for emphasis. Furthermore, the fear of seizure is not the sole cause; rather, it is combined with the fact that it belonged to the poor. It is like saying: "Zayd, I think, is staying."

It is mentioned in the readings of Ubayy and Abdullah: "Every sound ship."

{And as for the boy, his parents were believers, and we feared that he would burden them with transgression and disbelief. So we intended that their Lord should substitute for them one better than him in purity and closer in mercy. And as for the wall, it belonged to two orphan boys in the city, and there was beneath it a treasure for them, and their father had been righteous. So your Lord intended that they reach maturity and extract their treasure, as a mercy from your Lord. And I did not do it of my own accord. That is the interpretation of that about which you could not have patience.}