Sahih Muslim Book 26, Hadith Number 5417.

Chapter : Permission of seating a woman on the ride behind one’s back if one finds her completely exhausted in the way.

Asma’ daughter of Abu Bakr reported that the was married to Zubair. He had neither land nor wealth nor slave nor anything else like it except a horse. She further said: I grazed his horse, provided fodder to it and looked after it, and ground dates for his camel. Besides this, I grazed the camel, made arrangements for providing it with water and patched up the leather bucket and kneaded the flour. But I was not proficient in baking the bread, so my female neighbours used to bake bread for me and they were sincere women. She further said: I was carrying on my head the stones of the dates from the land of Zubair which Allah’s Messenger (may peace be upon him) had endowed him and it was at a distance of two miles (from Medina). She add: As I was one day carrying the atones of dates upon my head I happened to meet Allah’s Messenger (may peace be upon him) along with a group of his Companions. He called me and said (to the camel) to sit down so that he should make cite ride behind him. (I told my husband:) I felt shy and remembered your jealousy, whereupon he said: By Allah. the carrying of the stone dates upon your bead is more severe a burden than riding with him. She said: (I led the life of hardship) until Abu Bakr sent afterwards a female servant who took upon herself the responsibility of looking after the horse and I felt as it she had emancipated me.