Muhammad Would Never
It is probably fair to say that Muhammad did not approve of killing children intentionally. A verse from the Qur’an laments the pre-Islamic Arab practice of infanticide against baby girls, for example. Other evidence from the Hadith suggests that he instructed his men not to kill children in battle if it could be avoided, but to capture them for slavery.
While Muhammad told his people to “kill those who disbelieve in Allah,” children were often given a reprieve:
But Muhammad’s definition of a child was not the same as contemporary understanding. Following the surrender of the Qurayza stronghold, he ordered the execution of every male child who had reached puberty. His men had the boys drop their pants so that they could chop the head off of anyone with pubic hair (Abu Dawud 4390).
Keep in mind that many Muslims also insist that Aisha reached puberty at age nine, since that is the age that Muhammad began having sex with her. If so, then the age for “manhood” among boys might have been considered around twelve.
Muhammad played a bit loose with the lives of women and children during wartime. As recorded in both Bukhari and Sahih Muslim:
This does not justify the targeted killing of women and children per se, but it does prove that collateral damage is entirely acceptable if it accomplishes the military goal of spreading Islamic rule.
Muhammad used a catapult against the city of Taif – a catuplut kills indiscriminately. The only crime those citizens were guilty of was rejecting his claims of being a prophet and evicting him.
Muhammad drew a distinction between Muslim and non-Muslim children and implied that it would be permissible to kill a child who has no prospect of accepting Islam:
After capturing Mecca, the prophet of Islam also ordered the execution of two “singing girls” who had mocked him in verse: