The prohibition of divorcing a menstruating woman without her consent; If a man breaks this rule, it still counts as a divorce, and he should be ordered to take her back
وَحَدَّثَنَاهُ أَبُو الرَّبِيعِ، وَقُتَيْبَةُ، قَالاَ حَدَّثَنَا حَمَّادٌ، عَنْ أَيُّوبَ، بِهَذَا الإِسْنَادِ . نَحْوَهُ غَيْرَ أَنَّهُ قَالَ فَسَأَلَ عُمَرُ النَّبِيَّ صلى الله عليه وسلم فَأَمَرَهُ .
A hadith like this has been transmitted on the authority of Ayyub with a slight variation of words.