(Lo! now they fold up their breasts that they may hide (their thoughts) from Him…) [11:5].
This verse was revealed about al-Akhnas ibn Shurayq who was good looking and sweet talking. When he met the Messenger of Allah, Allah bless him and give him peace, he pleased him but he always kept in his heart that which displeased him. Al-Kalbi said: “He used to sit with the Prophet, Allah bless him and give him peace, and display things that pleased the Prophet while hiding in his heart the opposite of what he displayed. And so Allah, exalted is He, revealed (Lo! now they fold up their breasts that they may hide (their thoughts)) their thoughts of enmity to Muhammad, Allah bless him and give him peace”.
Asbab Al-Nuzul by Al-Wahidi , trans. Mokrane Guezzou