Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) says: "I climbed an arak tree to pick a tooth-stick (miswak) from it, and my companions began to marvel at how light I was, so the Prophet (peace and blessings be upon him) said: 'Why do you marvel? By the One in whose Hand is my soul, it will be heavier in the Scale on the Day of Resurrection than the mountain of Uhud.'"
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8485