Rav Huna son of Rav Kattina sat before Rav Chisda, and Rav Chisda cited "And he sent the young men of the children of Israel, who offered burnt-offerings, and sacrificed peace-offerings of oxen to the Lord," as an application of the proposition stated in the Mishnah that "before the Tabernacle was set up . . . the service was performed by the firstborn; after the tabernacle was set up . . . the service was performed by priests." (The "young men" in were the firstborn, not priests.) Rav Huna replied to Rav Chisda that Rabbi Assi taught that after that the firstborn ceased performing the sacrificial service (even though it was nearly a year before the Tabernacle was set up).