Deuteronomy 33:10
8 Of Levi he said: “Your Thummim and Urim belong to your godly one, whose authority you challenged at Massah, and with whom you argued at the waters of Meribah. 9 He said to his father and mother, ‘I have not seen him,’ and he did not acknowledge his own brothers or know his own children, for they kept your word, and guarded your covenant. 10 They will teach Jacob your ordinances and Israel your law; they will offer incense as a pleasant odor, and a whole offering on your altar. 11 Bless, O Lord, his goods, and be pleased with his efforts; undercut the legs of any who attack him, and of those who hate him, so that they cannot stand.” 12 Of Benjamin he said: “The beloved of the Lord will live safely by him; he protects him all the time, and the Lord places him on his chest.”
Haggai 2:11
9 “The future splendor of this temple will be greater than that of former times,” the Lord of Heaven’s Armies has declared. “And in this place I will give peace,” decrees the Lord of Heaven’s Armies. 10 On the twenty-fourth day of the ninth month of Darius’ second year, the Lord’s message came to the prophet Haggai: 11 “This is what the Lord of Heaven’s Armies has said, ‘Ask the priests about the law. 12 If someone carries holy meat in a fold of his garment and that fold touches bread, a boiled dish, wine, olive oil, or any other food, will that item become holy?’” The priests answered, “It will not.” 13 Then Haggai asked, “If a person who is ritually unclean because of touching a dead body comes in contact with one of these items, will it become unclean?” The priests answered, “It will be unclean.”
Notes and References
"... Before we turn to the phrase Oral Tora, it is necessary to pay attention to the word tora itself. In biblical Hebrew, the basic meaning of this word is 'instruction'. This may have either a specific meaning which also allows a plural (torot, teachings, laws), or a more general meaning (The book of this tora, Deuteronomy 28:61). Likewise, the prophet Haggai asks of 'the priests tora' (Haggai 2:11), and this appears to be nothing but instruction of the Sages (at that time, the priests) in matters of ritual purity. Post-biblical Hebrew retained these connotations of tora ... in a few instances, the term is ascribed to Tannaim and even to Shammai, but this is not the case in the Tannaic parallels to those passages. While the standard term is relatively late, there are early Tannaic traditions which contain other expressions of the same concept. In Sifrei we read: 'They shall teach... Israel Thy Tora (Deuteronomy 33:10) Two Torot were given to Israel, one in the mouth and the other in writing' ..."
Safrai, Shemuel "Oral Tora" in Safrai, Shemuel (ed.) The Literature of the Sages (pp. 35-119) Fortress Press, 1987