Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Ka'b Ahbar that he says: I found in the Book of God that any believing servant who goes to the mosque in the morning and evening, and his going to the mosque in the morning and evening is only to learn or teach goodness, or for the remembrance and contemplation of God, then his example in the Book of God is like that of a Mujahid in the way of Allah.