It is narrated from Sayyiduna Abdullah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "By the One in whose hand my soul is, on the Day of Resurrection the two shins of Ibn Mas'ud will be heavier and greater than Mount Uhud."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8421