Which law Paul?

The rabbis claim that oral Torah was also received by Moses from God on Mount Sinai and carries as much authority as the written Torah. 

However, this Torah was passed down through the centuries by word of mouthrather than the written word. Eventually this oral material was written down, culminating in the “written oral Torah” called the Talmud (תַּלְמוּד, “learning”) which consists of the Mishnah (מִשְׁנָה, “repetition”) and its commentary called the Gemarah (גְּמָרָה, “study”). Note that the Oral Torah is 50 times the size of the Written Torah!

Because it derives from the discussions of the Mishnah, the Talmud is also traditionally called Shas (ש“ס), an acronym for shisha sedarim, the “six orders” of the Mishnah. There exist two versions of Talmud: the Jerusalem Talmud (or “Yerushalmi”) and the Babylonian Talmud, or “Bavli” (the most frequently used version).

Within the Mishnah are two different types of literature. The first is known as halachah, or legal literature.Halachic literature interprets written Torah and seeks evidence to establish judicial laws, both civil and religious, that consist of codes of behavior and religious practice and procedures (for instance, the laws of marriage and divorce, the ethics of giving charity, etc.).

The second type of literature is know as Aggadah and is all material contained in the Talmud that is not halachah. It consists of the “wise sayings or tellings” of the sages. Aggadah includes stories, parables, theological or ethical statements, and homilies. Note that within the Talmud itself, both aggadah and halachah may be found mixed together, often with aggadah used to teach a principle based upon a halachic text.

The only authorized instructions are those that YHVH has given to us in Scripture, the rest, are mans attempt to insert themselves into places of importance.

This is the point Paul is making in Colossians.