Considering murtad.

I was discussing today with a French colleague the phenomena of 'muslims' becoming christian. This is considered a serious crime in the religion of Islam, but I am minded to attempt to moot an opinion. A child is born with Fitrah, thus can be said to be muslim as it is said all of nature is muslim, without thought or knowledge if you will. For an adult to be a muslim however, there is a requirement to utter the shahadah, and for this to be more than just movement of the lips. For the shahada to have any relevance it must be supported by a good and correct understanding of Tawheed, that being the basis of Islamic monotheism. Thus there are probably many people born in Muslim countries with l'air of the deen of Islam who are not muslim at all, as they lack the requirement of knowledge to validate their kalima. My French colleague was telling me that he knew 'muslims' that had become Christian, to which I replied that he could not, he of course argued the point that he did, to which I replied that if they were able to become Christian, then they lacked the intellectual requirements to be muslim, and thus had not left the deen of Islam, they had never been muslim in the first instance, other than as a child and in the same way as the tree, the earth, the sun, moon, and stars.