Musnad Ahmad 1167:26

Abu Usamah narrated to us, he said: Hisham ibn Urwah narrated to us, he said: My father informed me, from Asma bint Abi Bakr, she said: Al-Zubayr married me, and he had no wealth on earth, nor a slave, nor anything other than his horse. She said: So I used to feed his horse, suffice him of its care, tend to it, and crush date pits for his water-drawing camel. I would feed it, draw water, patch his water skin, and knead dough, but I was not good at baking. So, some female neighbors of the Ansar used to bake for me, and they were truthful women. I used to carry the date pits from the land of Al-Zubayr, which the Messenger of Allah (peace and blessings of Allah be upon him) had granted him, upon my head, and it was two-thirds of a farsakh away from me. She said: One day I came while the date pits were upon my head, and I met the Messenger of Allah (peace and blessings of Allah be upon him) with a group of his companions. He called me, then said: "Ikh, ikh" (a sound to make a camel kneel), so that he might carry me behind him. She said: I felt shy to travel with the men, and I remembered Al-Zubayr and his jealousy, for he was the most jealous of people. The Messenger of Allah (peace and blessings of Allah be upon him) realized that I had felt shy, so he went on. I came to Al-Zubayr and said: The Messenger of Allah (peace and blessings of Allah be upon him) met me while the date pits were upon my head, and he had a group of his companions with him. He made his camel kneel for me to ride with him, but I felt shy and remembered your jealousy. He said: "By Allah, your carrying the date pits was more severe upon me than your riding with him." She said: Until Abu Bakr sent me a servant after that, who sufficed me of the care of the horse, and it was as if he had set me free.