What is permitted (halal) and what is prohibited (haram); what is sacred and what is not; which way of worship are proper and which improper—all these matters have been made absolutely clear by God through His prophets. Any changes in these matters are not permissible. Any change made in these things is highly wrong, in the eyes of God. Therefore, it is necessary for man to follow the Prophet’s instructions. He should in no case increase or decrease what is prescribed by the Prophet. These are matters the reality of which is known only to God. When a man on his own says something on this subject, he virtually claims, in effect, to have knowledge about things of which he has no knowledge. Obviously, what wrong can be greater than this.