First of all, we would like to clarify that Khadijah, the mother of the believers, may Allah be pleased with her, was one of the early Muslim female women who believed in Islam and helped to spread the nascent Islamic Da`wah. She was the first woman who testified that there is no god but Allah and that Muhammad is the Messenger of Allah. She helped the Prophet in all what she can to help spread Islam and its universal message.

“When Prophet Muhammad (peace and blessings be upon him) was still a young man, she entrusted him with her wealth, asking him to trade with it on her behalf. At that time he was already well-known for his honesty, truthfulness and trustworthiness.

When Jibril first appeared to Prophet Muhammad, the Prophet went to Al Sayeda Khadijah and narrated what happened to her, as she listened to his words carefully, Khadijah did not feel any fear, instead she realized that something tremendous and awe-inspiring had happened to her husband, and she was certain, knowing him as she did, that he was neither mad nor possessed. “Do not worry,” she said, “for by Him who has dominion over Khadijah’s soul, I hope that you are the Prophet of this nation. Allah would never humiliate you, for you are good to your relatives, you are true in your word, you help those who are in need, you support the weak, you feed the guest and you answer the call of those who are in distress.”

Khadijah (may Allah be pleased with her) helped Prophet Muhammad, and supported him in every possible way, she sacrificed both her effort and money to spread Prophet Muhammad’s message, when Quraysh were infuriated by the Prophet’s success and did everything in their power to discourage him and his followers, often inflicting awful tortures on them, but in vain. But this gave Khadijah more strength and faith.
It is worthy mentioning here that Prophet Muhammad (peace and blessings be upon him) never stopped loving Khadijah, and although he married several more wives in later years and loved them all, Khadijah always had a special place in his heart. The Prophet said once to `Aishah (may Allah be pleased with her) about Khadijah:

“She believed in me when no one else did; she accepted Islam when people rejected me; and she helped and comforted me when there was no one else to lend me a helping hand.””