Syedna Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: Sulaiman bin Dawood (peace be upon him) said: Tonight I will go to a hundred women, each of whom will give birth to a boy who will fight in the way of Allah. But he forgot to say "In sha Allah" (if Allah wills). So he went to all the women and fulfilled his marital rights, but only one woman gave birth to a child, and even he was incomplete. Then the Prophet (peace and blessings be upon him) said: If he had said "In sha Allah," his oath would not have been broken and his need would have been fulfilled. In another narration, it is stated: If he had said "In sha Allah," then every woman would have given birth to a boy who would have fought in the way of Allah with a sword.