Musnad Ahmad 1304:21

Yazid ibn Harun narrated to us, he said: Ismail—meaning 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 Sa’d ibn Mu’adh passed away, his mother cried out. The Prophet, peace and blessings of Allah be upon him, said: "Will your tears not cease and your grief not depart? For your son is the first one for whom Allah laughed, and for whom the Throne shook."