That the Prophet ﷺ said: "It is not for a person to vow about that over which he has no control."
عَنِ النَّبِيِّ ﷺ قَالَ لَيْسَ عَلَى الْعَبْدِ نَذْرٌ فِيمَا لاَ يَمْلِكُ قَالَ وَفِي الْبَابِ عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو وَعِمْرَانَ بْنِ حُصَيْنٍ