Some people said that their marriage first was in the manner...

Some people said that their marriage first was in the manner of a brother with a sister marriage since Eve used to have a male and a female at every pregnancy and the rule with them was the marriage of the female of the next pregnancy with the male of the previous pregnancy and vice versa and a brother was not allowed to marriage the sister that was born with him at the same time.

Then the consideration of lawfulness and unlawfulness is not independent of thinking itself, but it is an act of the legislator and they are created laws, the legislator can put them up or cancel them because he is the source of legislation, so then what is unlawful is what God made unlawful and what is lawful is what He made lawful, so in the beginning of this matter it was lawful for the necessity and being among them only, but then after that it was made unlawful by God when they turned to be numerous and there was no count in the later religions for the necessity nor a criticizing for any difference in the laws.

In the beginning Adam let the brother get married to his sister by a commandment of God and it is lawful by the order of God and there should be no abomination because the laws were issued by Him and He is the source for them so no objection should be there from the created against the Creator, that is if this is the case. But what is mentioned from the Household members (PUT) is that it is forbidden and they opposed it furiously.

A questioner asked Al-Imam Al-Sadiq (PUH) and the questioner showed that the whole creation is in origin from brothers and sisters then said he (PUH): praise be to God, the Exalted, the High above all what they say, do they say that the best of God's creation and the prophets…