SB 5.11.7
tavan ayam vyavaharah sadavih
ksetrajña-saksyo bhavati sthula-suksmah
tasman mano lingam ado vadanti
gunagunatvasya paravarasya
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
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.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
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 manah krsna-padaravindayoh), 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 Krsna consciousness by the process of devotional service. We have often given the example of Ambarisa Maharaja. Sa vai manah krsna-padaravindayor vacamsi vaikuntha-gunanuvarnane. The mind must be controlled in Krsna consciousness. The tongue can be utilized to spread the message of Krsna and glorify the Lord or take prasada, the remnants of food offered to Krsna. Sevonmukhe hi jihvadau: when one utilizes the tongue in the service of the Lord, the other senses can become purified. As stated in the Narada-pañcaratra, sarvopadhi-vinirmuktam 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 Krsna’s service, one can be liberated and return home, back to Godhead.