we told moses to stay with us for thirty nights but added ten nights more so his appointment with his lord came to an end after forty nights. moses had appointed his brother aaron as his deputy among his people during his absence saying try to reform them and do not follow the way of the evildoers.
وواعدنا موسى ثلاثين ليلة وأتممناها بعشر فتم ميقات ربه أربعين ليلة وقال موسى لأخيه هارون اخلفني في قومي وأصلح ولا تتبع سبيل المفسدين