At Muslims and Muhammad - the Impossible Task, I posted, "It is impossible that a man could trade the Jewish wives and daughters of the men he had just beheaded for weapons and horses, and be a prophet of God."
Following Ibn Ishaq's description of Muhammad's beheading 600-900 Jewish men in Medina and dividing up their children, women, and property among the Muslims, discussed here, the Islamic historian continued as follows, "Then the Apostle sent Sa'd bin Zayd al-Ansari, brother of Abdel Ashhal, with some of the captive Jewish women of the tribe of Beni Qurayza to Najd, and he sold them for weapons and horses."
I would guess that 95 percent of Western Muslims would accuse anyone who described Muhammad as a slave trader as being a liar. Arabic Muslims in the Middle East, who know their own history much better than Westerners, do not deny but justify it.
How many captive Jewish women were taken as slaves to Najd and sold for weapons and horses? History does not record the number, but analysis can give a fair idea. Families were large in those days, so imagine that the average family contained six people, half of whom were female. As many as 900 males were beheaded, so easily 5,000 women and children could have remained. Muhammad's share of the booty was twenty percent, so 1,000 women and children could have been his. The others were divided among all of his followers, with the result that each Muslim received only a few slaves. Muhammad could not possibly utilize 1000 female slaves, so it is very likely that his own captives were the ones sent hundreds of miles across the desert to be traded for weapons and horses.
This is not an unreasonable number, because Ibn Ishaq elsewhere describes very large numbers of slaves captured and held by Muhammad. Following the capture of Taif, in which Muhammad's warriors for the first time used the catapult and a movable protective covering known as the testudo, the author notes that Muhammad held "six thousand women and children, and sheep and camels innumerable which had been captured from them". The women and children were returned to their husbands only after they accepted Islam. It is incredulous to imagine that these conversions, proclaimed to the man who had just captured their city, killed their peers, appropriated their property, stolen their livestock, and taken captive their wives and children, were motivated by true faith in Muhammad and Allah, but Muslims seem to have no trouble reaching that conclusion.
In the final analysis, of course, it makes do difference if the number of women and children sold was ten or ten thousand. I cannot believe that any understanding of the Golden Rule, which is treating others as you would want them to treat you, would justify selling even one person, much less a much larger number, for weapons and horses, and I cannot believe that a man who would do this could be a prophet of God.