عَنْ شُعْبَةَ قَالَ: جَاءَ رَجُلٌ إِلَى ابْنِ عَبَّاسٍ فَقَالَ: إِنَّ مَوْلَاكَ إِذَا سَحَدَ وَضَعَ جَبْهَتَهُ وَذِرَاعَيْهِ وَصَدْرَهُ بِالْأَرْضِ، فَقَالَ ابْنُ عَبَّاسٍ: مَا يَحْمِلُكَ عَلَى مَا تَصْنَعُ؟ قَالَ: التَّوَاضُعُ، قَالَ: هَٰكَذَا رِبْضَةُ الْكَلْبِ رَأَيْتُ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ إِذَا سَجَدَ رُؤِيَ بَيَاضُ إِبْطَيْهِ
Shu’bah says: A man came to Sayyiduna Abdullah bin Abbas (may Allah be pleased with him) and said: When your servant prostrates, he places his forehead, arms, and chest on the ground. He (Ibn Abbas) asked him: What makes you do this? He replied: I do it out of humility. Sayyiduna Ibn Abbas (may Allah be pleased with him) said: This is the posture of a dog. I saw the Noble Prophet (peace and blessings be upon him) that when he prostrated, the whiteness of his armpits would become visible.