All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
What you said was mentioned in a weak narration that was not confirmed as authentic. It was reported by Ad-Daarimi from ‘Uthmaan ibn ‘Affaan.
The verifying scholar, Shaykh Husayn Asad, said, “Its chain of narration is weak because Ibn Lahee'ah is a weak narrator.”
The Fatwa of the Standing Committee for Issuing Fataawa reads:
Question: “It was said that the Prophet used to recite verses 189 and 200 from Soorah Aal-‘Imraan every night, and Ad-Daarimi reported from ‘Uthmaan ibn ‘Affaan that he said, 'Whoever recites the last verses of Aal-‘Imraan in a night, it will be written for him as if he had prayed the whole night.'”
Answer: “We are not aware of any evidence that the Prophet used to recite verses 189 and 200 from Soorah Aal-‘Imraan in particular every night. As for the narration from ‘Uthmaan it was cited by Ad-Daarimi in his Sunan, and this was ‘Uthmaan’s statement [and not a hadeeth attributed to the Prophet]; Ad-Daarimi said, 'Is-haaq ibn ‘Eesa reported the above statement to us from Ibn Lahee’ah, from Yazeed ibn Abi Habeeb, from Abu al-Khayr, from ‘Uthmaan. Ibn Lahee’ah is a weak narrator, thus the chain of narrators is weak.”
Allaah knows best.