Narrated Anas:

Zaid bin Haritha came to the Prophet (ﷺ) complaining about his wife. The Prophet (ﷺ) kept on saying (to him), "Be afraid of Allah and keep your wife." Aisha said, "If Allah's Messenger (ﷺ) were to conceal anything (of the Qur'an he would have concealed this Verse." Zainab used to boast before the wives of the Prophet (ﷺ) and used to say, "You were given in marriage by your families, while I was married (to the Prophet) by Allah from over seven Heavens." And Thabit recited, "The Verse:-- 'But (O Muhammad) you did hide in your heart that which Allah was about to make manifest, you did fear the people,' (33.37) was revealed in connection with Zainab and Zaid bin Haritha."

Narrated Anas bin Malik:

The Verse: 'But you did hide in your mind that which Allah was about to make manifest.' (33.37) was revealed concerning Zainab bint Jahsh and Zaid bin Haritha.

Dawud reported on the same authorities the hadith as narrated above by Ibn 'Uliyya and added: She ('A'isha) said: If Muhammad were to conceal anything which was sent to him, he would have certainly concealed this verse:" And when thou saidst to him on whom Allah had conferred favour and thou too had conferred favour: Keep thy wife to thyself and fear Allah, and thou wast concealing in thy heart that which Allah was going to disclose, and thou wast fearing men while Allah has a better right that thou shouldst fear Him."