وَعَنْهَا قَالَتْ: «كَانَ رَسُولُ اَللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: إِذَا أَرَادَ سَفَرًا أَقْرَعَ بَيْنَ نِسَائِهِ، فَأَيَّتُهُنَّ خَرَجَ سَهْمُهَا، خَرَجَ بِهَا»
When the Messenger of Allah (sallallahu alayhi wa sallam) intended to go on a journey, he cast lots among his wives. Then, he would take with him the one who was chosen by the lot.
Bulugh al-Maram 1234, Book 8, Marriage, Hadith 112. 1 min read