"And you were not," O Muhammad, "on the western side," meaning the western side of the mountain, "when We decreed the command to Moses," meaning the message (risala), "and you were not among the witnesses," that is, you did not witness that.
﴿وَمَا كنت﴾ يَا مُحَمَّد ﴿بِجَانِب الغربي﴾ يَعْنِي: غَرْبِيَّ الْجَبَلِ ﴿إِذْ قَضَيْنَا إِلَى مُوسَى الْأَمر﴾ يَعْنِي: الرِّسَالَةَ ﴿وَمَا كُنْتَ مِنَ الشَّاهِدين﴾ أَي: لم تشاهد ذَلِك