وَكَيْفَ تَصْبِرُ عَلَىٰ مَا لَمْ تُحِطْ بِهِۦ خُبْرًا
Wa kaifa tasbiru 'alaa maa lam tuhit bihee khubraa
How could you be patient in matters beyond your knowledge?’
And how can you be patient with what you do not encompass in knowledge?
Khubra is knowledge got by going through a thing, and surah al-Kahf uses it twice with the same verb for encompassing: negated of Musa here, and at 18:91 stated of God, who encompasses everything Dhul-Qarnayn had with him. What is a limit at this verse returns as scope twenty-three verses later. The impatience being predicted is put down to what Musa has not been through, which leaves his character out of it.