SB 3.32.30

etad vai śraddhayā bhaktyā
 yogābhyāsena nityaśaḥ
samāhitātmā niḥsaṅgo
 viraktyā paripaśyati
Word for word: 
etat — this; vai — certainly; śraddhayā — with faith; bhaktyā — by devotional service; yoga-abhyāsena — by practice of yoga; nityaśaḥ — always; samāhita-ātmā — he whose mind is fixed; niḥsaṅgaḥ — aloof from material association; viraktyā — by detachment; paripaśyati — understands.
Translation: 
This perfect knowledge can be achieved by a person who is already engaged in devotional service with faith, steadiness and full detachment, and who is always absorbed in thought of the Supreme. He is aloof from material association.
Purport: 

The atheistic mystic practitioner of yoga cannot understand this perfect knowledge. Only persons who engage in the practical activities of devotional service in full Kṛṣṇa consciousness can become absorbed in full samādhi. It is possible for them to see and understand the actual fact of the entire cosmic manifestation and its cause. It is clearly stated here that this is not possible to understand for one who has not developed devotional service in full faith. The words samāhitātmā and samādhi are synonymous.