In Jesus' time there were 2 streams of Hebraic religion: 1. the Samaritans -- and yes, genetic studies show they have Israelite, even Cohen heritage. They hold to the Torah and reject the later writings
2. The Judeans
The Judeans or as we'd call them "The Jews" from 500 BC to 132 Ad had a number of sects:
1. The Sadducees -- the upholders of the Written Torah and the prophets writings etc
2. The Pharisees upholders of the Oral Torah - for instance the Written Torah says to keep the Sabbath holy but doesn't say how. The Pharisees elaborated on this and created a detailed law centuries later, the Halakha.
3. the Essenes - vegetarian, monastic, rejecting marriage for all. these are the ones Paul writes against.
4. the Zealots (later in the period 40 BC to 132 AD.
5. the Jesus-movement - future Christians
6. the followers of John the Baptist - future Mandaens
... other esoteric "Jewish" sects.
Only the Pharisees and the Jesus-movement sects survived.
the modern day Jews are derived from the Pharisees and revere the Talmud as deep scholarly and religious work - which it is, they have a strict Halakha and uphold the Written and Oral Torah.
The other sects died out with the destruction of the temple in 69 AD - except the Samaritans who had Mt Gerizim.
Now we are not endebted to the modern day Pharisee-derived Jews (refer to the Talmud and specifically the work of Rabbi Ben Zakkai on how he transformed Pharisee-Judaism) -- we are endebted to the 2nd temple Judaism -- and Christianity is a sect of that 2nd-temple Judaism a sister religion to modern-day post-2nd-temple Judaism
Indeed, but my post was not referencing post 132 AD but the Jews to whom we are indebted. And it was the the scribes and the Pharisees whom sat in Moses’ seat, to whom the Lord (like as to civil authorities) required conditional obedience, (Matthew 23:2) yet due to their false judgments and impenitence recalcitrance lost that authority to the sects which established its Truth claims upon Scriptural substantiation in word and in power. (2 Co. 6:4-10) As must the faith do continually.