Their chief energies were devoted to the study of the oral law in its definite form, the Mishna.
The oral law Moses continually taught in the Sanhedrim, to the elders and the rest of the people.
What is Revelation, and how did the sages apply it to the oral law?
They had no rabbis to keep them instructed in the countless prescriptions of the oral law and the incidence of days of observance.
They are a blending of the oral law of the Mishna and the notes and comments of the sages.
Clearly he is arguing here for the observance of the oral law, which later was standardized in the Halakah.
But the passage quoted in an earlier chapter, about adding to the law, proves his reverence for the oral law.
In his later years, he rejected many traditional observances of the oral law that completed his estrangement from the Pharisees.
Shamai replied, "We have two the written law and the oral law."