Speak the truth

The conclusion of this scripture [Srimad Bhagavatam] is that one should glorify Kåñëa. Other glorification, though not done badly, should not be done.  Glorification of the Lord even done badly by animalistic men should be done. Though material words are true, they are also false (måñä).  Though material words are sweet, they are painful (asaté).  Even if the words are uttered by learned persons, they are useless (asat-kathä).  Why?  Because they do not speak about Bhagavän.  Thus true words are false, sweet words are harsh and learned words are useless.  If the words are false, because they come from one’s imagination, but they glorify the Lord, then the words are true.  Though the words about Bhagavän are inauspicious because they destroy the householder’s world, they are actually auspicious words.  And though the irreligious say that speeches describing how the Lord takes others’ wives is impure, it is pure because those indicate good qualities in the Lord, not faults. 
(Srila Visvanatha Cakravarti Thakura's commentary on Srimad Bhagavatam, 12.12.49)