Musannaf Ibn Abi Shayba 17:1041

Abu Khalid al-Ahmar narrated to us, from Ibn ‘Ajlan, from ‘Abdullah ibn Dinar, from Abu Salih, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Faith is sixty or seventy or a few more—the narrator was uncertain which of the two numbers—the highest of which is the testimony that there is no god but Allah, and the lowest of which is removing an obstacle from the road. And modesty is a branch of faith."