The scribes in Matthew were simply some of the educated classes of the city, guys who knew how to read and write and do arithmetic, and they were often in positions of some authority because they could do those things, and they could do those things because they were either born into wealth or came up through the rabbinical ranks. Keep in mind that these are all jews, and the only thing truly sacred to them is money, so imagine a priesthood hierarchy based entirely on family wealth and you've got the rabbis of the ancient Middle East. And today.

The Scribes were literally copyists...or were supposed to be. Even Jeremiah warned of the lying pen of the Scribes.

Most mainstream adherents of Judaism in the Messiahs time were very stuck in unbiblical traditions, or they would focus on minute details of the law without addressing larger issues.

When the Messiah is asked what the greatest commandment is he answers not with any commandment, but the Shema which is found verbatim in Deuteronomy 6:4 He adds the second greatest commandment, which is also not one of the "10 commandments", but instead found in Leviticus 19:18, "love your neighbor as yourself".

Have fun reading.