A devotee always appreciates the activities of other devotees. Yudhisthira Maharaja was appreciating the qualities of Prahlada, and that is one symptom of a pure devotee. A pure devotee never thinks himself great; he always thinks that other devotees are greater than himself. The King was thinking, "Prahlada Maharaja is actually a devotee of the Lord, while I am nothing,"

>>> Ref. VedaBase => NoD, Attracting Krsna