Narrated Hudhaifa:

Allah's Messenger (ﷺ) said to us, "Honesty descended from the Heavens and settled in the roots of the hearts of men (faithful believers), and then the Qur'an was revealed and the people read the Qur'an, (and learnt it from it) and also learnt it from the Sunna." Both Qur'an and Sunna strengthened their (the faithful believers') honesty.