SB 10.68.21
ugrasenah ksiteseso
yad va ajñapayat prabhuh
tad avyagra-dhiyah srutva
kurudhvam avilambitam
Translation:
[Lord Balarama said:] King Ugrasena is our master and the ruler of kings. With undivided attention you should hear what he has ordered you to do, and then you should do it at once.