The Book of Prayers (Kitab Al-Salat)
Muslim :: Book 4 : Hadith 2010
'Abdullah b. 'Umar said that Sa'd b. Ubada complained of illness. The Messenger of Allah (may peace be upon him) came to visit him accompanied by 'Abd al-Rahman b. 'Auf, Sa'd b. Abi Waqqas and 'Abdullah b. Mas'ud. As he entered (his room) he found him in a swoon. Upon this he said: Has he died? They said: Messenger of Allah, it is not so. The Messenger of Allah (may peace be upon him) wept. When the people saw Allah's Messenger (may peace be upon him) weeping, they also began to weep. He said. Listen, Allah does not punish for the tears that the eye sheds or the grief the heart feels, but He punishes for this (pointing to his tongue), or He may show mercy.