SB 11.29.30

naitat tvayā dāmbhikāya
 nāstikāya śaṭhāya ca
aśuśrūṣor abhaktāya
 durvinītāya dīyatām
Word for word: 
na — not; etat — this; tvayā — by you; dāmbhikāya — to a hypocrite; nāstikāya — to an atheist; śaṭhāya — to a cheat; ca — and; aśuśrūṣoḥ — to one who does not listen with faith; abhaktāya — to a nondevotee; durvinītāya — to one who is not humbly submissive; dīyatām — should be given.
Translation: 
You should not share this instruction with anyone who is hypocritical, atheistic or dishonest, or with anyone who will not listen faithfully, who is not a devotee, or who is simply not humble.