those which have been prima facie laid down as such in the Qur'an and the teachings of the Prophe
and they multiplied those [additional] injunctions to such an extent that the religious law became a heavy burden on the community." For the sociological reason why the genuine ordinances of Islamic Law - that is, (those which have been prima facie laid down as such in the Qur'an and the teachings of the Prophet

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Question

those which have been prima facie laid down as such in the Qur'an and the teachings of the Prophe
and they multiplied those [additional] injunctions to such an extent that the religious law became a heavy burden on the community." For the sociological reason why the genuine ordinances of Islamic Law - that is, (those which have been prima facie laid down as such in the Qur'an and the teachings of the Prophet

Dont understand the sentence above in question?

Answer

The 'as such' refers back to  "ordinances", to avoid repeating it. 
So, you could perhaps read it as "(those ordinances which have been first written down as ordinances in the Qur'an and the teachings of the Prophet)"

Answer

prima facie = at first sight (= based on what seems to be the truth when first seen or heard)

In my opinion, you could put it this way:
For the sociological reason why the genuine ordinances of Islamic Law - that is, (the ordinances which seem to have been laid down as such in the Qur'an ...)

I hope this is helpful.