SB 11.3.49

Prāṇāyāma is the authorized Vedic process for controlling the air within the body. Similarly, bhūta-śuddhi is a process for purifying the body. The word śuciḥ means that one should be internally and externally clean. Śuciḥ means that one should perform activities only for the pleasure of the Supreme Personality of Godhead. If somehow or other one can remember the Supreme Lord constantly by chanting and hearing His holy name, one will come to the pure stage of life, as described in this Vedic mantra: om apavitraḥ pavitro vā sarvāvasthāṁ gato ’pi vā yaḥ smaret puṇḍarīkākṣaṁ sa bahyābhyantara-śuciḥ ( Garuḍa Purāṇa ) Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura has pointed out that although one may mark the body with sacred tilaka, perform mudrās and chant mantras, if one is thinking within his mind of material sense gratification his worship of Lord Śrī Hari is bogus. Therefore the word śuciḥ here indicates that one should worship the Lord in a favorable frame of mind, considering the Lord to be sacred and one’s self to be an insignificant servant of the Lord. Those who are not favorably inclined toward the Supreme Personality of Godhead do not like to worship the Deity in the temple, and they discourage people from going to the temple of the Lord by saying that since the Lord is omnipresent there is no need to do so. Such envious persons prefer the gymnastic exercises of haṭha-yoga or the rāja-yoga system. But statements by the Lord Himself, such as vāsudevaḥ sarvam iti and māṁ ekaṁ śaraṇaṁ vraja, indicate that in mature transcendental realization one understands that the Supreme Personality of Godhead is the source of everything and therefore the only worshipable object. Thus the devotees who worship the Deity of the Lord according to the paṣcarātra system are not attracted by any yoga process except bhakti-yoga.