Musannaf Ibn Abi Shayba 34:162

Muhammad ibn al-Hasan al-Asadi narrated to us, Abu 'Awanah narrated to us, from Abu Kathir, from Mujahid, who said: The beginning of creation was the Throne, the water, and the air. The earth was created from the water. The beginning of creation was Monday, Tuesday, Wednesday, and Thursday, and the creation was gathered on Friday. The Jews became Jews on Saturday. And a day of the six days is like a thousand years of what you count.