Narrated Ibn `Abbas:
If someone says to his wife, "You are unlawful to me." he must make an expiation (for his oath). Ibn `Abbas added: There is for you in Allah's Messenger (ﷺ), an excellent example to follow. (PT)
USC-MSA web (English) reference: Vol. 6, Book 60, Hadith 433 (PT)
Arabic reference (PT): Book 65, Hadith 4911 (PT)