The scribes and Pharisees, being closet atheists, affected to be believers unto men, and pretended like they would not commit the least sin while transgressing the whole of the law, said the Lord. Because there was, to them, no God, they felt free to preach their own wisdom, learning, precepts, and commandments for popularity and money, since the scriptures were false: God did not give the law and commandments to Moses, and they would face no final accounting of their handling of God's law and commandments nor for their teachings to the people.
Of course, the common people, who were the majority of the scribes' and Pharisees' paying audience, did believe in God, and so the priestcrafters had to step carefully, always being seen to be on the side of the most popular opinions - whenever they were unable to control the popular perception of the meaning and course of events, or "the narrative." Because the majority of the people seemed to think Jesus a prophet, they greeted Jesus before the people as "master," or "rabbi." And their alterations to the law - eventually compiled in the Talmud (their equivalent of the LDS Church Handbook of Instructions) - came by mischaracterizing and deliberately interpreting the law and commandments of God as draconian, unmerciful, or nonsensical, and substituting their own wisdom and commandments in the place thereof, always in ways to make themselves appear more merciful / wise / just than God, allow for the rich to keep their mammon in contradiction to the commandments (the rich, you see, pay their preachers more per capita than the poor), and advance their own power in the community. "Believe it not; do it not" was the sum of their teachings, "... but do what we say instead; we'll show you how to succeed in the world."
As an aside, the Pharisees were the leftists / progressives / "living document" nonliteralists of their day. The Sadducees were the right / conservatives / traditionalists / literalists (they didn't believe in the resurrection because it wasn't clearly taught in the scriptures they had). The Essenes would have roughly corresponded to today's "alt-right" movement.
However, consider the problem the Pharisees' interpretation of the law and commandments of God posed for them, if their teachings were taken literally. God, if we take the scribes and Pharisees seriously, is in effect saying "I do not want what I say I want." That is, God is a liar: nothing he says is to be taken literally... unless it suits your purposes to take him literally.
Why give commandments at all, or even communicate, then, one might ask. And that is an excellent question, one that has only one answer - to such, there is no God. The law and commandments are simply foolish traditions handed down because of the childishness of the fathers. To such, religion is a huge scam for money and power, selling an imaginary product to ignorant and superstitious rubes, and why not play the game to the hilt since there is no God save it be mammon?