that the Messenger of Allah ﷺ said: "He was called Al-Khadir because he sat on a barren Farwah and it turned green beneath him."
قَالَ رَسُولُ اللَّهِ ﷺ إِنَّمَا سُمِّيَ الْخَضِرَ لأَنَّهُ جَلَسَ عَلَى فَرْوَةٍ بَيْضَاءَ فَاهْتَزَّتْ تَحْتَهُ خَضْرَاءَ