Professor Ansarian:
Hazrat Khadija (A.S) had excelled in the understanding the facts, this great and noble lady spent all her properties and assets in the way of Allah Almighty and Islam and at the time her demise she was weeping on an old carpet fearing lest Allah Almighty maybe unhappy with her, and when the Gabriel sent her Allah,s greetings, she asked the holy Prophet peace be upon him and his progeny to give her his clothes a shroud.
Hazrat Khadija (A.S) is the first lady who embraced Islam. At the same time that the holy prophet (PBUH) was suffering the harassment and bothering of the infidels, Hazrat Khadija (SA) was the only one who reduce the sorrow and grief of the holy prophet (PBUH) and that,s why she was named the permanent helper of the Holy prophet peace be upon him and his progeny. Her smile made the prophet forget his pains and suffering and he was soothed. When Hazrat Khadija (A.S) believed in Holy prophet and his mission as the first Muslim woman, the holy prophet was more determined in doing and following his prophetic mission. She drew a glorious and promising future for her husbands mission.
At the time when the women of ignorance era were afflicted to different kinds of immorality and debauchery of that time, Hazrat Khadija (A.S), even before marrying the holy prophet, was known as a pure woman (tahereh) - a person who is free from all impurity and debauchery. Ibn Abbas says: "The Messenger of Allah drew four lines on the ground and asked: Do you know what this is? They said: Allah and His Messenger are more aware, we do not know. Prophet said: The best women of Paradise are four persons: “Khadija the daughter Khuwaylid, Fatima the daughter of Muhammad, Mary the daughter of Emran and Asiya the daughter of Mozahem"
source : erfan.ir