One verse

Srimad Bhagavatam 11.29.30

11.29.30

नैतत्त्वया दाम्भिकाय नास्तिकाय शठाय च । अशुश्रूषोरभक्ताय दुर्विनीताय दीयताम् ॥ ३० ॥

naitat tvayā dāmbhikāya nāstikāya śaṭhāya ca aśuśrūṣor abhaktāya durvinītāya dīyatām

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

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.