Excerpts from "The Sealed Nectar"
Muhammad Sallallahu Alaihi Wasallam had no particular job at his early youth, but it was reported that he worked as a shepherd for Bani Sa'd and in Makkah for a wage.
At the age of 25, he went to Syria as a merchant for Khadijah. Ibn Ishaq reported that Khadijah, daughter of Khuwailid was a businesswoman of great honour and fortune. She used to employ men to do her business for a certain percentage of the profits.
The Quraish were merchants, so when Khadijah Radi Allahu anha was informed of Muhammad Sallallahu Alaihi Wasallam, his truthful words, great honesty and kind manners, she sent for him. She offered him money to go to Syria and do business for her, and she would give him a higher rate than the others. She would also send her servant, Maisarah, with him. He agreed and went with her servant to Syria for trade.