tvaḿ tu mad-dharmam āsthāya
jñāna-niṣṭha upekṣakaḥ
man-māyā-racitām etāḿ
vijñayopaśamaḿ vraja
tvam -- you; tu -- however; mat-dharmam -- in My devotional service; asthaya -- remaining firm; jnana-nishthah -- fixed in knowledge; upekshakah -- indifferent; mat-maya -- by My illusory energy; racitam -- created; etam -- this; vijnaya -- understanding; upasamam -- cessation from agitation; vraja -- obtain.
According to Srila Jiva Gosvami, the word tu here emphasizes that Daruka is an eternally liberated associate of Lord Krishna, having descended from Vaikuntha. Therefore, even though others might be bewildered by the Lord's pastimes, Daruka should remain peaceful and fixed in spiritual knowledge.