Sahih al-Bukhari Book 78, Hadith 35

I never felt so jealous of any woman as I did of Khadija, though she had died three years before the Prophet married me, and that was because I heard him mentioning her too often, and because his Lord had ordered him to give her the glad tidings that she would have a palace in Paradise, made of Qasab and because he used to slaughter a sheep and distribute its meat among her friends.