Narrated Abu Huraira:

The Prophet ﷺ said, "Allah has forgiven my followers the evil thoughts that occur to their minds, as long as such thoughts are not put into action or uttered." And Qatada said, "If someone divorces his wife just in his mind, such an unuttered divorce has no effect.:

حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا هِشَامٌ، حَدَّثَنَا قَتَادَةُ، عَنْ زُرَارَةَ بْنِ أَوْفَى، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ عَنِ النَّبِيِّ ﷺ قَالَ
" إِنَّ اللَّهَ تَجَاوَزَ عَنْ أُمَّتِي مَا حَدَّثَتْ بِهِ أَنْفُسَهَا، مَا لَمْ تَعْمَلْ أَوْ تَتَكَلَّمْ ". قَالَ قَتَادَةُ إِذَا طَلَّقَ فِي نَفْسِهِ فَلَيْسَ بِشَىْءٍ.