וְאֶל־צִדְקִיָּ֤ה מֶֽלֶךְ־יְהוּדָה֙ דִּבַּ֔רְתִּי כְּכָל־הַדְּבָרִ֥ים הָאֵ֖לֶּה לֵאמֹ֑ר הָבִ֨יאוּ אֶת־צַוְּארֵיכֶ֜ם בְּעֹ֣ל מֶֽלֶךְ־בָּבֶ֗ל וְעִבְד֥וּ אֹת֛וֹ וְעַמּ֖וֹ וִֽחְיֽוּ׃
我也照著這一切話對猶大王西底家說：«要把你們的頸項放在巴比倫王的軛下，服事他和他的百姓，就可以存活。»
Epistle of Rav Sherira Gaon
And after Rav Huna (רב הונא) in Babylon, Mar Rav Ukva (מר רב עוקבא) was appointed. And Shmuel (שמואל) was with him, as we say: Shmuel and Mar Ukva, when they sat and learned, Mar Ukva would sit before Shmuel at his four cubits. And when they sat in judgment, Shmuel would sit before Mar Ukva at his four cubits. And we say: Shmuel said to Rav Yehudah (רב יהודה), "Sharp one! Your head is in cold water, and the head of your master is in hot water. Behold, Mar Ukva and his court exist, and it is written concerning them, 'Thus says the Lord, O house of David, execute justice in the morning.'"