It is narrated from Sayyidah Asma bint Yazid bin al-Sakan (may Allah be pleased with her), a woman of the Ansar, that when the funeral of Sa'd bin Mu'adh (may Allah be pleased with him) was brought out, his mother cried out. The Messenger of Allah (peace and blessings be upon him) said to her: "Let your tears cease and your grief depart, for your son is the first one at whom Allah laughed and for whom the Throne shook."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20838