I have been living in Britain for four years, and a few months ago I decided to become a Christian! But I did not do it. When I made that decision, I was saying to myself: If any of them asks me, what is your religion, I will say that I am a Christian and that Jesus is the “son of God” (I ask Allah to forgive me for that). But I also used to say to myself: No; Islam is the only true religion. 

Then one day I heard an exhortation of yours on YouTube, and it moved me deeply. I cancelled that intention that I had made to become Christian; in other words, I did not go to the church and did not do anything of that nature. 

My question is: are the words that I said to myself sufficient to have made me become a Christian? And therefore do I have to go to a mosque and utter the twin declaration of faith (shahaadatayn)?


Praise be to Allah

We praise Allah, may He be exalted, for having opened your
eyes to the seriousness of what you did and your decision to turn to a
religion other than Islam, and for His blessing you so that you changed your
mind before it was too late. We would like to point out two things to you
here: 

Firstly: 

What you did of deciding to become a disbeliever, and making
your mind up to become a Christian constitutes apostasy from the religion of
Islam, even if you did not actually enter the church or do any of the other
actions that Christians do. Merely deciding to disbelieve constitutes
disbelief in Allah, may He be exalted. The same applies to a person’s
indecision as to whether he should turn to another religion or remain in
Islam. 

Imam an-Nawawi (may Allah have mercy on him) said: Deciding
to become a disbeliever in the future constitutes disbelief in the present.
The same applies to indecision as to whether to disbelieve or not; it
constitutes disbelief in the present. That also applies to making disbelief
conditional upon some future matter.

End quote from Rawdat at-Taalibeen, 10/65. Something
similar was said in Nihaayat al-Muhtaaj and elsewhere. See also:
Majma‘ al-Anhaar
(a Hanafi book), 1/688 

In Haashiyat al-Bujayrimi ‘ala al-Khateeb it says: 

Intending to disbelieve now or to disbelieve in the future
constitutes disbelief in the present, because intending to be a Muslim
forever is essential, so if he decides to disbelieve (in the future), he has
already disbelieved. 

In Haashiyat al-Jamal (5/122) it says something
similar. 

Secondly: 

It is not one of the conditions of your repentance that you
should announce that in the mosque or Islamic centre, especially since you
made that decision in your own mind and it did not result in spreading
disbelief or mischief among the Muslims. As that is the case, it is
sufficient for you to repent sincerely to your Lord, may He be glorified and
exalted, to utter the Shahaadatayn, and adhere to the religion of Allah, may
He be exalted, in all your affairs, and to disbelieve in all other
religions. 

If you do ghusl before that, that would be good, in sha
Allah. 

We advise you to seek knowledge and devote yourself to acts
of worship and obedience, because the one who does that will increase and
strengthen his faith. You should also be keen to offer supplication
(du‘aa’), for it is the weapon of the believer, by means of which Allah will
ward off evil from you and will protect you, by virtue of your remembrance
of Him, from the tricks of your enemy and His enemy. 

And Allah knows best.