Musannaf Ibn Abi Shayba 21:332

Sulayman ibn Hayyan Abu Khalid al-Ahmar narrated to us, from Yahya ibn Sa'id, from Abu al-Zubayr, from Tawus, from Mu'adh, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "No deed that the son of Adam performs is more saving for him from the Fire than the remembrance of Allah." They said: "O Messenger of Allah, not even Jihad in the way of Allah?" He said: "Not even Jihad in the way of Allah, unless you strike with your sword until it breaks, then you strike with your sword until it breaks, then you strike with it until it breaks."