Praise be to Allah.
Inna Lillahi wa inna ilayhi raji’oon (Verily to Allah we belong and unto Him is our return). We ask Allah to keep us safe and sound in this world and in the Hereafter, and we ask Him for a good end and to cause us to die in faith.
You should realize that you have fallen into the worst and most abhorrent of sins, which is the sin of kufr (disbelief) and apostasy, Allah forbid.
The words which you say that you said are a clear statement of kufr and apostasy. The scholars said: When a person utters the words of kufr, he is judged to be an apostate (if he knew the meaning of the words) and he need not be asked about his intention, as Allah says (interpretation of the meaning):
“If you ask them (about this), they declare: ‘We were only talking idly and joking.’ Say: ‘Was it at Allah, and His ayat (proofs, evidences, verses, lessons, signs, revelations, etc.) and His Messenger that you were mocking?”
Allah stated that they disbelieved after having believed, even though they said, “We spoke the words without believing them, we were only talking idly and joking.”
Ibn Nujaym said: Whoever speaks the words of kufr, jokingly or otherwise, is a kafir according to all the scholars, and it doesn’t matter what his real belief is. End quote. Al-Bahr al-Raiq. See also Nawaqid al-Eeman al-Qawliyyah wa’l-‘Amaliyyah.
Al-Shaykh Ibn ‘Uthaymeen said:
If he utters words that put him beyond the pale of Islam, such as saying that he is a Jew or a Christian or Magian or that he has nothing to do with Islam, or with the Quran or the Prophet (peace and blessings of Allah be upon him), then he is a kafir and an apostate, and we take him at his word. End quote. Al-Sharh al-Mumti’
Apostasy is an extremely serious matter. The scholars differed concerning one who apostatizes then repents: will any of the reward for his previous deeds remain, or is it all erased because of his apostasy?
Al-Shaykh al-Fawzan was asked the following question:
What is the ruling on one who apostatizes from Islam then returns to it? Should he repeat his previous deeds in accordance with the pillars of Islam, such as Hajj, fasting and prayer, or is it sufficient for him to repent and return to Islam?
The correct scholarly view is that if the apostate returns to Islam and enters Islam anew, repenting to Allah, then he does not need to repeat the deeds that he did before apostatizing, because Allah has stipulated that in order for deeds to be cancelled out by apostasy, the person has to die as an apostate.
Allah says (interpretation of the meaning):
“And whosoever of you turns back from his religion and dies as a disbeliever, then his deeds will be lost in this life and in the Hereafter, and they will be the dwellers of the Fire. They will abide therein forever.”
So in order for deeds to be lost, it is stipulated that a person persist in apostasy until he dies in that state. The verse indicates that if a person repents then the deeds that he did before apostatizing are still valid and will be rewarded insha Allah. End quote.
Al-Muntaqa min Fatawa al-Fawzan
With regard to slapping the face, this is a deed of Jahiliyyah (pre-Islamic age of ignorance) which the Prophet (peace and blessings of Allah be upon him) warned against. It is narrated that the Prophet (peace and blessings of Allah be upon him) disavowed himself of the one who does this, as he said: “He is not one of us who slaps his cheeks, rends his garment and calls out with the cry of the Jahiliyyah.” [al-Bukhari].This indicates that slapping the cheeks is a major sin.
As you regret what you did, we hope that Allah will accept your repentance. You have to utter the Shahadatayn (twin declaration of faith) in order to re-enter Islam after going out of it. You have to do good deeds and guard your tongue, for a person may say a word that angers Allah but he regards it as insignificant, then he will be thrown into the Fire and will continue falling down into it for seventy years.
With regard to expiation, there is no expiation for what you have done apart from repentance, regret and resolve not to do it again.
We ask Allah to accept your repentance and to enable you to adhere to His religion.
And Allah knows best.
And Allah knows best.