catur-vidha bhajante mam,  janah sukritino 'rjuna
arto jijnasur artharthi,  jnani ca bharatarshabha

O best among the Bharatas [Arjuna], four kinds of pious men render devotional service unto Me -- the distressed, the desirer of wealth, the inquisitive and he who is searching for knowledge of the Absolute. (BG 7.16)