It is narrated from Sayyiduna Anas bin Malik, may Allah be pleased with him, that the Messenger of Allah, peace and blessings be upon him, said: "The days were presented to me (in their specific forms), among them was the day of Friday, which was like a white glass, and in its middle was a black dot. I said: What is this? It was said to me: This is the Day of Resurrection."