It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that if a person declares his wife forbidden upon himself, then this is an oath for which he should give expiation (his wife will not be divorced), and he used to present this verse as evidence: «﴿لَقَدْ كَانَ لَكُمْ فِي رَسُولِ اللَّهِ أُسْوَةٌ حَسَنَةٌ﴾ [الأحزاب : 21]» "Indeed, in the Messenger of Allah you have an excellent example."