It was narrated that Abu Hurairah said:
"The Messenger of Allah (ﷺ) said: 'Faith has sixty-some or seventy parts, the least of which is to remove a harmful thing from the road and the greatest of which is to say La ilaha illalah (none has the right to be worshipped but Allah). And modesty is a branch of faith.'"Another chain from Abu Hurairah, from the Prophet (ﷺ) with similar wording. (ID)
English reference (ID): Vol. 1, Book 1, Hadith 57 (ID)
Arabic reference (ID): Book 1, Hadith 59 (ID)