Another example of Jesus’ observance of the Oral Torah was his adherence to the rabbinic prohibition against using the Unutterable Name of God.
The original understanding of the third commandment, “You shall not take the name of the LORD your God in vain” (Exod. 20:7), was that one must keep one’s vows when swearing by God’s name. Israel’s ancient sages eventually came to interpret this commandment to mean using the LORD’s name lightly or frivolously. To avoid the risk of employing the divine name irreverently, the sages ruled that one should not utter it at all.
The tetragrammaton, YHVH, could be pronounced only in the Temple (Sifre Numbers 39), in the daily priestly blessing (Mishnah, Sotah 7:6), and in the confession of the high priest on the Day of Atonement (Mishnah, Yoma 6:2). When reading or reciting Scripture, one was not to pronounce the Unutterable Name, but rather, was to substitute אֲדֹנָי (Adonai, Lord, literally, “my lords”).
This avoidance of the tetragrammaton began very early. Although there was no hesitation about pronouncing the Sacred Name in daily life during the First Temple period, by the third century B.C., Adonai was being substituted for YHVH. (For a discussion of the original pronunciation of the divine name, see my “‘Jehovah’: A Christian Misunderstanding.”)