حَدَّثَنَا حَسَنُ بْنُ مُوسَى حَدَّثَنَا زُهَيْرٌ عَنْ أَبِي إِسْحَاقَ عَنِ التَّمِيمِيِّ الَّذِي يُحْدِثُ التَّفْسِيرَ عَنِ ابْنِ عَبَّاسٍ قَالَ أَتَيْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مِنْ خَلْفِهِ فَرَأَيْتُ بَيَاضَ إِبْطَيْهِ وَهُوَ مُجَخٍّ قَدْ فَرَّجَ يَدَيْهِ
مسند امام احمد بن حنبل · Hadith 2405
It was narrated that Ibn 'Abbas (RA) said: I came to the Messenger of Allah (PBUH) from behind and I saw the whiteness of his armpits when he was rostrating with his arms held away from his body.
Translated by Dr. Muhammad Muhsin Khan · Reviewed by Islamic University of Madinah · Published March 2020