Moses (as)...
Moses (as), who regretted for his haste, which was naturally for the importance of the event, remembered his promise and tried to excuse. He turned to the godly teacher and said: “He said: ‘Do not take me to task that I forgot, and be not hard upon me for my affair’.” The voyage of those two (Moses and Khidr) ended and they got out of the ship. They continued their way on the land. In their way, occasionally they met a young boy whom that learned man (Khidr) suddenly killed.
The holy verse in this regard says: “So they twain departed; until, when they met a lad, he (Khidr) slew him. Here, Moses (as) became inconvenient again. He saw the horrible scene of killing an innocent young boy, which had no legal permission. As if a curtain of sorrow and discontentment had fallen upon his eyes. It was so hard for him that he forgot his promise again and began protesting against that action. The verse says: “…He (Moses) said: ‘Slew you an innocent person who had slain none?
“He (Moses) said: ‘If I question you on anything after this, then keep me company no more; you have received an excuse from me’.” That great godly learned man repeated the former sentence with the same coolness particular to himself. The holy verse says: “He (Khidr) said: ‘Did I not say that you could never bear with me patiently?’” Moses (as) remembered his own promise to him. It was an attention accompanied with shame, because he had broken his promise twice, although forgetfully.
Little by little, Moses (as) felt the teacher might be right. Therefore, he began asking forgiveness again and told Khidr to renounce him his forgetfulness that time, too. But if thereafter he (Moses) wanted him (Khidr) any explanation concerning his affairs, and objected to him upon his deeds, he would keep him company no more, since Khidr had received an excuse from Moses (as).
The verse says: “He (Moses) said: ‘If I question you on anything after this, then keep me company no more; you have received an excuse from me’.” This holy phrase of the Qur’an leads us to the utmost justice and far-sightedness of Moses (as), and it also shows that he accepted the reality even if it had been bitter.