She Said to Her Husband ‘O Kaafir’
13-4-2021 | IslamWeb
Question:
Aoa respected sheikh i want to ask is my marriage nullifies if by mistake i say kafir to my husband.ACtually i did not know that saying kafir is forbidden and did not know about ahadith i was having argument with my husband and because i misunderstand his words so i said u r kafir after this he made me aware of my mistakes and showed all ahadith and narration now im very repentful y i used this word i did not mean so i prayes salat ul tauba im so repentfl just guide me is my nikkah is save or do i have to do shahadah and tajdeed e nikkah.before i was not aware about saying kafir to muslim is forbidden know i have knowledge and repentful of saying in ignorance and by mistake my husband kafir actually i wnted to say that u r talking and thinking like non muslim instead i used word kafir.kindly guide me about my marriage and what to do nect after repenting.
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad 
is His slave and Messenger.
What you have mentioned has no effect on the validity of marriage. There is a Hadeeth about considering a Muslim as a non-Muslim, which was reported by Al-Bukhari and Muslim on the authority of Ibn ‘Umar that the Prophet said: “If a man says to his Muslim brother: “O, Kafir! (Disbeliever)”, then one of the two will have Kufr drawn on him.”
The scholars stated that the word of Kufr in the Hadeeth refers to the minor Kufr; they provided evidence with the Hadeeth of Thaabit ibn Adh-Dhahhaak reported by Al-Bukhari that the Prophet said: “Cursing a believer is like killing him, and if a person says to his brother “O, Kaafir! (Disbeliever)”, then it is like killing him.”
Killing is not Kufr (disbelief), and he likened it to declaring a believer as a non-Muslim.
The Hadeeth is a threat and severe warning against declaring a believer as a non-Muslim [but it does not mean that one really becomes a non-Muslim].
Therefore, you do not need to worry about the matter of marriage, but you must beware of returning to such a thing again in the future.
Allah knows best.