Sayyiduna Ibn Umar (may Allah be pleased with them both) narrates: The Throne (of Allah) shook out of love for Sayyiduna Sa'd's (may Allah be pleased with him) meeting with Allah. And last of them all, the Prophet (peace and blessings be upon him) came out from his grave and said: "Sa'd was squeezed once in his grave, so I asked Allah Almighty to lighten it for him."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13498