Sahih al-Bukhari Book 67, Hadith 175
(The Prophet) Solomon son of (the Prophet) David said, "Tonight I will go round (i.e. have sexual
relations with) one hundred women (my wives) everyone of whom will deliver a male child who will
fight in Allah's Cause." On that an Angel said to him, "Say: 'If Allah will.' " But Solomon did not say
it and forgot to say it. Then he had sexual relations with them but none of them delivered any child
except one who delivered a half person. The Prophet (ﷺ) said, "If Solomon had said: 'If Allah will,' Allah
would have fulfilled his (above) desire and that saying would have made him more hopeful."