If one of you marries a woman or buys a slave, he should say: "O Allah, I ask You for the good in her, and in the disposition You have given her; I take refuge in You from the evil in her, and in the disposition You have given her." When he buys a camel, he should take hold of the top of its hump and say the same kind of thing.

Abu Dawud said: Abu Sa'id added the following words in his version: He should then tale hold of her forelock and pray for blessing in the case of a woman or a slave.
Sunan Abi Dawud Book 12, Hadith 115
← Previous Hadith The aforesaid tradition has also been transmitted by Ibn Ishaq through a different chain of narrators. This version has the traditional word “a menstrual course” in the phrase “till she is free from a menstrual course”. This is a misunderstanding on the part of the narrator Abu Mu’awiyah. This is correct in the tradition of Abu Sa’id Al Khudri. This version has the additional words “he who believes in Allaah and the Last Day should not ride on a mount belonging to the spoil of Muslims and when he makes it emaciated returns it; he who believes in Allaah and the Last Day should not put on cloth belonging to the spoils of Muslims and when makes it old (shabby) returns it.

Abu Dawud said “The word “menstrual course” is not guarded. This is a misunderstanding on the part of Abu Mu’awiyah”

Sunan Abi Dawud Book 12, Hadith 114 Next Hadith → Ibn ‘Abbas reported the Prophet (ﷺ) as saying “If anyone who means to have intercourse with his wife says “In the name of Allaah, O Allaah, keep us away from the devil and keep the devil away from what You hast provided us.” It will be ordained that no devil will ever harm the child born to them.

Sunan Abi Dawud Book 12, Hadith 116