Volume 1, Book 3, Number 74:
Narrated Ibn 'Abbas:
That he differed with Hur bin Qais bin Hisn Al-Fazari regarding the companion of (the Prophet) Moses. Ibn 'Abbas said that he was Khadir. Meanwhile, Ubai bin Ka'b passed by them and Ibn 'Abbas called him, saying "My friend (Hur) and I have differed regarding Moses' companion whom Moses, asked the way to meet. Have you heard the Prophet mentioning something about him? He said, "Yes. I heard Allah's Apostle saying, "While Moses was sitting in the company of some Israelites, a man came and asked him. "Do you know anyone who is more learned than you? Moses replied: "No." So Allah sent the Divine Inspiration to Moses: 'Yes, Our slave Khadir (is more learned than you.)' Moses asked (Allah) how to meet him (Khadir). So Allah made the fish as a sign for him and he was told that when the fish was lost, he should return (to the place where he had lost it) and there he would meet him (Al-Khadir). So Moses went on looking for the sign of the fish in the sea. The servant-boy of Moses said to him: Do you remember when we betook ourselves to the rock, I indeed forgot the fish, none but Satan made me forget to remember it. On that Moses said: 'That is what we have been seeking? (18.64) So they went back retracing their foot-steps, and found Khadir. (And) what happened further to them is narrated in the Holy Qur'an by Allah. (18.54 up to 18.82)
Chapter 18 - "The Cave"
18.54: And certainly We have explained in this Quran every kind of example, and man is most of all given to contention.
18.55: And nothing prevents men from believing when the guidance comes to them, and from asking forgiveness of their Lord, except that what happened to the ancients should overtake them, or that the chastisement should come face to face with them.
18.56: And We do not send apostles but as givers of good news and warning, and those who disbelieve make a false contention that they may render null thereby the truth, and they take My communications and that with which they are warned for a mockery.
18.57: And who is more unjust than he who is reminded of the communications of his Lord, then he turns away from them and forgets what his two hands have sent before? Surely We have placed veils over their hearts lest they should understand it and a heaviness in their ears; and if you call them to the guidance, they will not ever follow the right course in that case.
18.58: And your Lord is Forgiving, the Lord of Mercy; were He to punish them for what they earn, He would certainly have hastened the chastisement for them; but for them there is an appointed time from which they shall not find a refuge.
18.59: And (as for) these towns, We destroyed them when they acted unjustly, and We have appointed a time for their destruction.
18.60: And when Musa said to his servant: I will not cease until I reach the junction of the two rivers or I will go on for years.
18.61: So when they had reached the junction of the two (rivers) they forgot their fish, and it took its way into the sea, going away.
18.62: But when they had gone farther, he said to his servant: Bring to us our morning meal, certainly we have met with fatigue from this our journey.
18.63: He said: Did you see when we took refuge on the rock then I forgot the fish, and nothing made me forget to speak of it but the Shaitan, and it took its way into the river; what a wonder!
18.64: He said: This is what we sought for; so they returned retracing their footsteps.
18.65: Then they found one from among Our servants whom We had granted mercy from Us and whom We had taught knowledge from Ourselves.
18.66: Musa said to him: Shall I follow you on condition that you should teach me right knowledge of what you have been taught?
18.67: He said: Surely you cannot have patience with me
18.68: And how can you have patience in that of which you have not got a comprehensive knowledge?
18.69: He said: If Allah pleases, you will find me patient and I shall not disobey you in any matter.
18.70: He said: If you would follow me, then do not question me about any thing until I myself speak to you about it
18.71: So they went (their way) until when they embarked in the boat he made a hole in it. (Musa) said: Have you made a hole in it to drown its inmates? Certainly you have done a grievous thing.
18.72: He said: Did I not say that you will not be able to have patience with me?
18.73: He said: Blame me not for what I forgot, and do not constrain me to a difficult thing in my affair.
18.74: So they went on until, when they met a boy, he slew him. (Musa) said: Have you slain an innocent person otherwise than for manslaughter? Certainly you have done an evil thing.
18.75: He said: Did I not say to you that you will not be able to have patience with me?
18.76: He said: If I ask you about anything after this, keep me not in your company; indeed you shall have (then) found an excuse in my case.
18.77: So they went on until when they came to the people of a town, they asked them for food, but they refused to entertain them as guests. Then they found in it a wall which was on the point of falling, so he put it into a right state. (Musa) said: If you had pleased, you might certainly have taken a recompense for it.
18.78: He said: This shall be separation between me and you; now I will inform you of the significance of that with which you could not have patience.
18.79: As for the boat, it belonged to (some) poor men who worked on the river and I wished that I should damage it, and there was behind them a king who seized every boat by force.
18.80: And as for the boy, his parents were believers and we feared lest he should make disobedience and ingratitude to come upon them:
18.81: So we desired that their Lord might give them in his place one better than him in purity and nearer to having compassion.
18.82: And as for the wall, it belonged to two orphan boys in the city, and there was beneath it a treasure belonging to them, and their father was a righteous man; so your Lord desired that they should attain their maturity and take out their treasure, a mercy from your Lord, and I did not do it of my own accord. This is the significance of that with which you could not have patience.