Musannaf Ibn Abi Shayba 36:266

Muhammad ibn Fudayl narrated to us, from ‘Ata’ ibn al-Sa’ib, from Mujahid, from Ibn ‘Umar, who said: "The Throne shook due to the love of Sa’d for meeting Allah." He said: "And he raised his parents upon the Throne." He said: "Its supports cracked." He said: "The Messenger of Allah (peace be upon him) entered his grave and was delayed. When they said, 'O Messenger of Allah, what delayed you?' he said: 'Sa’d was squeezed in the grave with a squeeze, so I supplicated to Allah to relieve him of it.'"