The Pharisees are a hyper-strict sect of Jews, endeavoring to keep the law better than anyone else ever had.
If you read through the OT and then into the Gospels, it’s odd to find a Jew of any stripe following the Law, especially more strictly than intended.
Most of the OT shows Jewish people rebelling, not listening to God and usually worshipping idols. To then flip the page to Matthew and see Pharisees is just odd.
Perhaps the explanation lies in human nature and our leaning to go to extremes. After coming out of such monumental failure, a brand of Jews gets together to be the best Jews ever.
Perhaps this desire to be obedient, better than any other Jew, is what created Pharisaism.
It reminds me of people today who were brought up in legalistic traditions. Often they flip over to hyper-grace churches, or churches where there is an abundance of liberty, often bordering on licentiousness.
On the flip side, many who are brought up in “anything goes” brands of Christianity often gravitate toward legalistic branches.
The reason why there are legalistic branches and license branches of faith is because Christianity is a mix of both. We have liberty in Christ, and yet Paul says to bring your body under subjection.
There are rules, there is a requirement for obedience and submission, and at the same time there is liberty in Christ. We are indeed under the “perfect law of liberty!”
Don’t chuck liberty for law and don’t chuck law for liberty; use em both as they were intended.