The Practical “Classes” Commence
فَانطَلَقَا حَتَّى إِذَا رَكِبَا فِي السَّفِينَةِ خَرَقَهَا قَالَ أَخَرَقْتَهَا لِتُغْرِقَ أَهْلَهَا لَقَدْ جِئْتَ شَيْئًا إِمْرًا
And so the two went on their way, till [they reached the seashore; and] when they disembarked from the boat [that had ferried them across], Khadir made a hole in it – [whereupon Musa عليه السلام] exclaimed: “Hast thou made a hole in it in order to drown the people who may be [travelling] in it? Indeed, thou hast done a grievous thing!” [Al Kahf 18:71]

Prophet Musa عليه السلام ‘protested’ at the way Khadir was, ‘apparently’, returning the good deed done to them by the people on the boat – who let them take a ride on it,- by making a hole in it. As we know, making a hole in a boat makes it completely useless, because it can cause those riding in it to drown.

Musa عليه السلام was sincere at heart, which was why he could not adhere to his earlier claim of not asking Khadir any questions about what he saw him doing. He was promptly reprimanded by his teacher/mentor:

قَالَ أَلَمْ أَقُلْ إِنَّكَ لَن تَسْتَطِيعَ مَعِيَ صَبْرًا
He replied: “Did I not tell you that you will never be able to have patience with me?” [Al Kahf 18: 72]
The sincere student (who, remember, happens to be Allah’s Prophet) immediately realizes and admits his unintentional slip, then seeks forgiveness and pardon from his teacher:

قَالَ لَا تُؤَاخِذْنِي بِمَا نَسِيتُ وَلَا تُرْهِقْنِي مِنْ أَمْرِي عُسْرًا
Musa عليه السلام said: “Pardon my forgetfulness, and do not be angry with me on account of this mistake.” [Al Kahf 18: 73]
Thankfully, Khadir granted him pardon and took him along for further learning:

فَانطَلَقَا حَتَّى إِذَا لَقِيَا غُلَامًا فَقَتَلَهُ قَالَ أَقَتَلْتَ نَفْسًا زَكِيَّةً بِغَيْرِ نَفْسٍ لَّقَدْ جِئْتَ شَيْئًا نُّكْرًا
“And so the two went on, till, when they met a young man, Khadir killed him, [whereupon Musa] exclaimed: “Have you slain an innocent human being without [his having taken] another man’s life? Indeed, you have done a terrible thing!” [Al Kahf 18: 74]
Once again, Prophet Musa عليه السلام was not able to contain himself, and he protested about this apparently undeserved death in shock. He once again got promptly reprimanded, with Khadir reminding him how he had correctly predicted Musa’s عليه السلام lack of patience (صَبْر):

قَالَ أَلَمْ أَقُل لَّكَ إِنَّكَ لَن تَسْتَطِيعَ مَعِي صَبْرًا
He replied: “Did I not tell you that you will never be able to have patience with me?” [Al Kahf 18: 75]

Realizing his folly, Prophet Musa عليه السلام pleaded with Khadir to let him continue in his company, and in his zeal to prove his sincere regret at breaking the preset rule, and his resolve to not ask any more questions/voice any protests, he made his mentor an offer:

قَالَ إِن سَأَلْتُكَ عَن شَيْءٍ بَعْدَهَا فَلَا تُصَاحِبْنِي قَدْ بَلَغْتَ مِن لَّدُنِّي عُذْرًا
Musa عليه السلام said: “If, after this, I should ever question you, keep me not in your company: [for by] now you have heard enough excuses from me.” [Al Kahf 18: 76]
فَانطَلَقَا حَتَّى إِذَا أَتَيَا أَهْلَ قَرْيَةٍ اسْتَطْعَمَا أَهْلَهَا فَأَبَوْا أَن يُضَيِّفُوهُمَا فَوَجَدَا فِيهَا جِدَارًا يُرِيدُ أَنْ يَنقَضَّ فَأَقَامَهُ قَالَ لَوْ شِئْتَ لَاتَّخَذْتَ عَلَيْهِ أَجْرًا
“And so the two went on, till, when they came upon some village people, they asked them for food; but those [people] refused them all hospitality. And they saw in that (village) a wall which was on the point of tumbling down, and [Khadir] rebuilt it [whereupon Musa] said: “Had you so wished, surely you could [at least] have obtained some payment for it?” [Al Kahf 18: 77]
Oops. He did it again.

قَالَ هَذَا فِرَاقُ بَيْنِي وَبَيْنِكَ سَأُنَبِّئُكَ بِتَأْوِيلِ مَا لَمْ تَسْتَطِع عَّلَيْهِ صَبْرًا
Khadir replied: “This is the parting of ways between me and you. [And now] I shall let you know the real meaning of all [those events] that you were unable to bear with patience.” [Al Kahf 18: 78]

As per their agreement, this third, involuntary lapse of patience meant an end to his lessons with Khadir.
This is the incident that transpired, over the next few days we will in sha Allah take a look at the various lessons which can be derived from the incidents.