"And when you reach the time of the noon prayer": the Dhuhr prayer.
Muhammad said: You say: 'Az-harna' (we have entered the midday), meaning: We have entered the time of the midday heat, and it is the time of the sun's meridian (zawal).
Yahya said: 'This verse was revealed after the Prophet, peace be upon him, was taken on the Night Journey (Isra'), and the five daily prayers were made obligatory upon him. Every prayer mentioned in the Meccan part of the Qur'an before the five prayers were made obligatory consists of two rak'ahs in the morning and two rak'ahs in the evening.'
﴿وَحين تظْهرُونَ﴾ صَلَاةَ الظُّهْرِ.
قَالَ مُحَمَّدٌ: تَقُولُ: أَظْهَرْنَا؛ أَيْ: دَخَلْنَا فِي الظَّهِيرَةِ؛ وَهُوَ وَقْتُ الزَّوَالِ.
قَالَ يَحْيَى: " نزلت هَذِه الْآيَة بعد مَا أسرِي بِالنَّبِيِّ عليه السلام وَفُرِضَتْ عَلَيْهِ الصَّلَوَاتُ الْخَمْسُ، وَكُلُّ صَلَاةٍ ذُكِرَتْ فِي الْمَكِّيِّ مِنَ الْقُرْآنِ قَبْلَ أَنْ تُفْتَرَضَ الصَّلَوَاتُ الْخَمْسُ فَهِي رَكْعَتَانِ غُدْوَةً، وَرَكْعَتَانِ عَشِيَّة ".
