Musnad Ahmad 8:11

Hassan narrated to us, Ibn Lahi'ah narrated to us, Yazid ibn Abi Habib narrated to us, from Dawud ibn Amir ibn Sa'd ibn Abi Waqqas, from his father, from his grandfather, from the Prophet (peace and blessings of Allah be upon him), who said: "If what could be carried by a fingernail of what is in Paradise were to appear, it would have adorned everything between the horizons of the heavens and the earth. And if a man from the people of Paradise were to look out and his bracelet were to appear, its light would have extinguished the light of the sun, just as the sun extinguishes the light of the stars."