The ceremonisation of marriage, according to Islam, is not as limited as most of the Mualimins believe. The fact is that when non-Muslims become Muslims, their marriage is not repeated, and their children are always taken in as legitimate. So if the marriage ceremony held, according to their own custom, was not legitimate, how could their children be considered legitimate by Islam?
So it is totally an erroneous, false idea. What Islam requires is that a regular marriage ceremony should be held in accordance with the local customs or the customs of a And if that is not a crime, according to the social order in which that marriage is ceremonised, then it is not a crime from any religious point of view either.
But those who are already Muslims and know a better way and a definite form of ceremonisation, if they intentionally ignore it to an inferior system, and knowing that Islam requires this, that is in itself a crime, but of a smaller order which will not affect the fact of marriage, which will remain valid.
