Sahih Bukhari
Oneness, Uniqueness of Allah (Tawheed)
Volume: 009 / Book Number: 093 / Hadith Number: 576
Narrated 'Aisha:
I never felt so jealous of any woman as I felt of Khadija, for Allah ordered him (the Prophet ) to give Khadija the glad tidings of a palace in Paradise (for her).