Narrated `Ali
I heard Allah's Messenger (ﷺ) saying (as below) Narrated `Ali: The Prophet (ﷺ) said, "The best of the world's women is Mary (at her lifetime), and the best of the world's women is Khadija (at her lifetime).
Narrated `Aisha
I did not feel jealous of any of the wives of the Prophet (ﷺ) as much as I did of Khadija (although) she died before he married me, for I often heard him mentioning her, and Allah had told him to give her the good tidings that she would have a palace of Qasab (i.e. pipes of precious stones and pearls in Paradise), and whenever he slaughtered a sheep, he would send her women-friends a good share of it.
Narrated `Aisha
I did not feel jealous of any woman as much as I did of Khadija because Allah's Messenger (ﷺ) used to mention her very often. He married me after three years of her death, and his Lord (or Gabriel) ordered him to give her the good news of having a palace of Qasab in Paradise.
Narrated `Aisha
I did not feel jealous of any of the wives of the Prophet (ﷺ) as much as I did of Khadija though I did not see her, but the Prophet (ﷺ) used to mention her very often, and when ever he slaughtered a sheep, he would cut its parts and send them to the women friends of Khadija. When I sometimes said to him, "(You treat Khadija in such a way) as if there is no woman on earth except Khadija," he would say, "Khadija was such-and-such, and from her I had children."
Narrated Isma`il
I asked `Abdullah bin Abi `Aufa, "Did the Prophet (ﷺ) give glad tidings to Khadija?" He said, "Yes, of a palace of Qasab (in Paradise) where there will be neither any noise nor any fatigue."
Narrated Abu Huraira
Gabriel came to the Prophet (ﷺ) and said, "O Allah's Messenger (ﷺ)! This is Khadija coming to you with a dish having meat soup (or some food or drink). When she reaches you, greet her on behalf of her Lord (i.e. Allah) and on my behalf, and give her the glad tidings of having a Qasab palace in Paradise wherein there will be neither any noise nor any fatigue (trouble). "
Narrated 'Aisha
Once Hala bint Khuwailid, Khadija's sister, asked the permission of the Prophet (ﷺ) to enter. On that, the Prophet (ﷺ) remembered the way Khadija used to ask permission, and that upset him. He said, "O Allah! Hala!" So I became jealous and said, "What makes you remember an old woman amongst the old women of Quraish an old woman (with a teethless mouth) of red gums who died long ago, and in whose place Allah has given you somebody better than her?"