Sahih Muslim 495 b
The Book of Prayers
The Description Of The Prayer, With What It Begins And Ends. The Description Of Bowing And Moderation Therein, And Of Prostration And Moderation Therein. Tashah-hud After Each Two Rak'ah Of Four Rak'ah Prayers. Description Ol Sitting Between The Two Prostrations, And In The First Tashah-hud
This hadith has been narrated by Ja'far b. Rabi' with the same chain of transmitters. And in the narration transmitted by 'Amr b. al-Harith (the words are): " When the Messenger of Allah (rtiay peace be upon him) prostrated, he spread out his arms so that the whiteness of his armpits was visible." And in the narration transmitted by al-Laith (the words are:" When the Messenger of Allah (ﷺ) prostrated. he spread his hands from the armpits so that I saw their whiteness."