Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Ibn Masood (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: Those who love each other for the sake of Allah will be on pillars of red ruby on the Day of Resurrection. On top of the pillars will be seventy thousand rooms; they will look upon the people of Paradise. When any one of them looks, the beauty of his face will fill the dwellings of the people of Paradise, just as the light of the sun fills the houses of the people of the world. Then a dweller of Paradise will say: Bring before us those who loved each other for the sake of Allah. Then they will be brought forth; their faces will be like the full moon of the fourteenth night. They will be wearing green garments, and on their foreheads it will be written: These are the people who loved each other for the sake of Allah.