Al-Kahf: (70)

(He said: "Then if you follow me") Al-Khidr (peace be upon him) granted him permission to follow after the long struggle and persistence. The Fa (then) is for grounding the conditional clause upon what preceded regarding Musa’s (peace be upon him) promise of patience and obedience.

(Do not ask me about anything) that you witness of my actions, let alone debating or turning away, (until I myself mention it to you) – meaning, until I initiate the explanation of it for you.

The limit (the until) is, as it is said, set for what the speech implies; it is as if it were said: "Keep your internal disapproval of what I do until I clarify it for you." Alternatively, it signifies the permanent cessation of questioning, for questioning is certainly not appropriate after the explanation has been given. In both views, it serves as an indication that everything emanating from him has a wisdom and a praiseworthy purpose, without exception. It has been said that hatta (until) is for causal explanation, but this is baseless.

Nafi' and Ibn Amir recited fala tas'alanni with the heavy nun (doubled) and a glottal stop. From Abu Ja'far is fala tasalanni, with the sin, lam, and nun all vocalized with fatha and the nun doubled, without a glottal stop. All the reciters, as Abu Bakr stated, recite it with a ya at the end. Regarding Ibn Abbas (may Allah be pleased with them both), there is an unusual report concerning the omission of the ya.