Wail b, hujr said that he prayed behind the Messenger of Allah ﷺ,and he said Amin loudly and saluted at his right and left sides until I saw the whiteness of his cheek.
أَنَّهُ صَلَّى خَلْفَ رَسُولِ اللَّهِ ﷺ فَجَهَرَ بِآمِينَ وَسَلَّمَ عَنْ يَمِينِهِ وَعَنْ شِمَالِهِ حَتَّى رَأَيْتُ بَيَاضَ خَدِّهِ