Deuteronomy 4:2

Ye shall not add to the word which I command you, nether shall you diminish ought from it ,.... Neither make new laws of their own, and join them to the law of God, and set them upon a level with it, or prefer them before it; as the Scribes and Pharisees did in Christ's time, who by their traditions made the word of God of none effect, as do the Papists also by their unwritten traditions; nor abrogate nor detract from the law of God, nor make void any part of it: or else the sense is, neither do that which is forbidden, nor neglect that which is commanded; neither be guilty of sins of omission nor commission, nor in any way break the law of God, and teach men so to do by word or by example; not a jot or tittle is either to be put to it, or taken from it, Proverbs 30:5 .

that ye may keep the commandments of the Lord your God, which I command you ; in his name; or which he delivered unto them as his commandments, and which were to be kept just as they were delivered, without adding to them, or taking from them.