Musannaf Ibn Abi Shayba 36:268

Yazid ibn Harun narrated to us, he said: Ismail ibn Abi Khalid informed us, from Ishaq ibn Rashid, from a woman of the Ansar who is called Asma bint Yazid ibn Sakan, she said: When the funeral of Sa'd ibn Mu'adh went out, his mother cried out. The Messenger of Allah (may Allah bless him and grant him peace) said to the mother of Sa'd: "Will your tears not cease and your grief not depart? Indeed, your son is the first one for whom Allah laughed and for whom the Throne shook."