Sahih Muslim, 2523

Rapporté par Umm Salama رضي الله عنها : Le Messager d’Allah ﷺ a juré de ne pas aller chez certaines de ses épouses pendant tout un mois. Après vingt-neuf jours, il est allé les voir, soit le matin, soit le soir. On lui a alors dit : « Ô Messager d’Allah, tu avais juré de ne pas venir pendant un mois. » Il a répondu : « Un mois peut aussi compter vingt-neuf jours. »

Umm Salama (Allah be pleased with him) reported that the Messenger of Allah (ﷺ) took an oath that he would not go to some of his wives for the whole of the month. When twenty-nine days bad passed he (the Holy Prophet) went to them in the morning or in the evening. Upon this it was said to him:Apostle of Allah, you took an oath that you would not come to us for a month, whereupon he said: The month may also consist of twenty-nine days