Drdha means very firm, steady. Krsna is so kind that He has given us so many concession. But we should be… Because there are some concession, better we should not take advantage of the concession, but we should be very steady and strong in our conviction and perform devotional service strictly.
>>> Ref. VedaBase => Srimad-Bhagavatam 1.5.1-8 — New Vrindaban, May 23, 1969