दातव्यमिति यद्दानं दीयतेऽनुपकारिणे। देशे काले च पात्रे च तद्दानं सात्त्विकं स्मृतम् ॥

dātavyam iti yad dānaṁ dīyate ‘nupakāriṇe deśhe kāle cha pātre cha tad dānaṁ sāttvikaṁ smṛitam

That alms given to one who does nothing in return, believing that a gift ought to be made in a fit place and time to a worthy person, that alms is accounted pure.

In plain words: A gift is pure when it is given because giving is right, to a worthy person, at the right time and place, and to someone who cannot repay you.