From Sahih Muslim (Hadith 153):
It is narrated on the authority of Abu Huraira that the Messenger of Allah (may peace and blessings be upon him) said:Faith has over seventy branches or over sixty branches, the most excellent of which is the declaration that there is no god but Allah, and the humblest of which is the, removal of what is injurious from the path: and modesty is the branch of faith
Reference: Muslim 153