kṣetrajña-sākṣyo bhavati sthūla-sūkṣmaḥ
tasmān mano liṅgam ado vadanti
tāvān — until that time; ayam — this; vyavahāraḥ — the artificial designations (being fat or skinny, or belonging to the demigods or human beings); sadā — always; āviḥ — manifesting; kṣetra-jña — of the living entity; sākṣyaḥ — testimony; bhavati — is; sthūla-sūkṣmaḥ — fat and skinny; tasmāt — therefore; manaḥ — the mind; liṅgam — the cause; adaḥ — this; vadanti — they say; guṇa-aguṇatvasya — of being absorbed in material qualities or devoid of material qualities; para-avarasya — and of lower and higher conditions of life.
The mind makes the living entity within this material world wander through different species of life, and thus the living entity experiences mundane affairs in different forms as a human being, demigod, fat person, skinny person and so forth. Learned scholars say that bodily appearance, bondage and liberation are caused by the mind.
Just as the mind is the cause of bondage, it can also be the cause of liberation. The mind is described here as para-avara, para means transcendental, and avara means material. When the mind is engaged in the Lord’s service (sa vai manaḥ kṛṣṇa-padāravindayoḥ), it is called para, transcendental. When the mind is engaged in material sense gratification, it is called avara, or material. At the present moment, in our conditioned state, our mind is fully absorbed in material sense gratification, but it can be purified and brought to its original Kṛṣṇa consciousness by the process of devotional service. We have often given the example of Ambarīṣa Mahārāja. Sa vai manaḥ kṛṣṇa-padāravindayor vacāṁsi vaikuṇṭha-guṇānuvarṇane. The mind must be controlled in Kṛṣṇa consciousness. The tongue can be utilized to spread the message of Kṛṣṇa and glorify the Lord or take prasāda, the remnants of food offered to Kṛṣṇa. Sevonmukhe hi jihvādau: when one utilizes the tongue in the service of the Lord, the other senses can become purified. As stated in the Nārada-pañcarātra, sarvopādhi-vinirmuktaṁ tat-paratvena nirmalam: when the mind and senses are purified, one’s total existence is purified, and one’s designations are also purified. One no longer considers himself a human being, a demigod, cat, dog, Hindu, Muslim and so forth. When the senses and mind are purified and one is fully engaged in Kṛṣṇa’s service, one can be liberated and return home, back to Godhead.