BT Ḥul 15a(35) :אטו כולי עלמא לתנא צייתי לאמורא צייתי‏ : does everyone listen to the Tanna [i.e. the transmitter of the Oral Law]? They listen to the Amora [i.e. the speaker]
See the entire entry for ṣwt vb. to listen