The Prophet (ﷺ) said: To harbour good thoughts is a part of well-conducted worship. (This is according to Nasr's version).

Abu Dawud said: Mahna' is reliable and he is from Basrah.
Sunan Abi Dawud Book 43, Hadith 221
← Previous Hadith The Prophet (ﷺ) said: It is enough falsehood for a man to relate everything he hears.

Abu Dawud said: Hafs did not mention Abu Hurairah (in his version).

Abu Dawud said: No other transmitter except this old man, that is, 'Ali b. Hafs al-Mada'ini related the perfect chain of this tradition.

Sunan Abi Dawud Book 43, Hadith 220 Next Hadith → The Messenger of Allah (May peace be upon him) was in the I’TIKAF(seclusion in the mosque). I came to visit him at night . I talked to him, got up and turned my back. He got up with me to accompany me. He was living in the house of Usamah b. Zaid. Two men of the Ansar passed by him. When they saw the Messenger of Allah (May peace be upon him), they walked quickly. The prophet (May peace be upon him) said: Be at ease; she is Safiyyah daughter of Huyayy. They said: Glory be to Allah, Messenger of Allah! He said: The devil flows in man as the blood flows in him. I feared that he might inject something in your hearts, or he said “evil” (instead of something).

Sunan Abi Dawud Book 43, Hadith 222