Al Kahf

قَالَ أَلَمْ أَقُل لَّكَ إِنَّكَ لَن تَسْتَطِيعَ مَعِيَ صَبْراً

قَالَ إِن سَأَلْتُكَ عَن شَيْءٍ بَعْدَهَا فَلاَ تُصَاحِبْنِي قَدْ بَلَغْتَ مِن لَدُنّـِي عُذْراً

75. “He (Khidr) said: ‘Did I not say that you could never bear with me patiently?’”
76. “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:

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:

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. An Islamic tradition indicates that the holy Prophet of Islam (S) recited this verse and said that Moses, the prophet of Allah, ashamed. If he had waited and bore patience, he would have seen thousand wonderful actions from Khidr.¹