Jerusalem Talmud Hagigah 1:8 (76a): Revelation of the Oral Law

Greco-Roman Period
This passage shows how the Rabbis understood both halakhah and aggadah to be part of the oral Torah, given by God at Sinai.

Rabbi Joshua ben Levi said,” ‘Upon them’—‘And upon them’; ‘all’—‘according to all’;
‘words’—‘the words.’ Scripture, Mishnah, Talmud, halakhah, and aggadah. Even that
which an experienced student will teach, has already been taught to Moses at Sinai.” 127

126. Trans. S. Berrin.

127. Deut. 9-10, describing the writing on the tablets of the Ten Commandments, says,
“And on them was written according to all the words which the Lord spoke with you on
the mountain.” Rabbi Joshua noted that it does not simply say “Upon them” but “And
upon them”; not simply “all” but “according to all”; not simply “words” but “the
words.” He says that these apparently superfluous words were added to teach that the
revelation at Sinai included much more than the Ten Commandments themselves,
namely, Scripture, Mishnah, etc.