The word ātmā denotes body, mind and soul—depending upon different circumstances. In the yoga system, the mind and the conditioned soul are especially important. Since the mind is the central point of yoga practice, ātmā refers here to the mind. The purpose of the yoga system is to control the mind and to draw it away from attachment to sense objects. It is stressed herein that the mind must be so trained that it can deliver the conditioned soul from the mire of nescience. In material existence one is subjected to the influence of the mind and the senses. In fact, the pure soul is entangled in the material world because the mind is involved with the false ego, which desires to lord it over material nature. Therefore, the mind should be trained so that it will not be attracted by the glitter of material nature, and in this way the conditioned soul may be saved. One should not degrade oneself by attraction to sense objects. The more one is attracted by sense objects, the more one becomes entangled in material existence. The best way to disentangle oneself is to always engage the mind in Kṛṣṇa consciousness.
(Bhagavad-Gita---6:5---purport).

Lord Kapila said: The senses are symbolic representations of the demigods, and their natural inclination is to work under the direction of the Vedic injunctions. As the senses are representatives of the demigods, so the mind is the representative of the Supreme Personality of Godhead. The mind's natural duty is to serve. When that service spirit is engaged in devotional service to the Personality of Godhead, without any motive, that is far better even than salvation.
(Srimad Bhagavatam--3:25:32---translation).

One should learn gravity from the sea and the rivulet. The sea is always within its limits, in spite of the many rivers pouring water into it. Similarly, one should properly use the assets of life and not squander them for purposes that have no permanent value. Uncontrolled, sensuous persons play with the assets of the body and accumulate wealth. But the strength of the body should be used for self-realization, not for sense gratification.
Human beings have two kinds of temperament. Some are introspective, and the others are extravagant. Those who are extravagant are enamored of the external features of phenomenal beauty and have no insight into the whole manifestation. They are practically asleep to introspection, and thus they are unable to derive any permanent value from the assets of the human form of body. But one who has developed introspection is as grave as the sea. While those who are extravagant are calm and quiet in sleep, such grave persons use the full advantage of the human form of life.
Although the animal propensities of the body should be minimized, those who are extravagant temporarily overflow in material enjoyment. Nonetheless, as soon as the rainy season of life is over, they become as dry as dry river beds. Life is meant for the right cause, or sat—that which exists for all time. In the material world, nothing is sat, or eternal, but the bad bargain of the material world can be used for the best purpose. The mind dedicated to extravagance is a bad bargain, but one can make the best use of the mind by introspection.
(Light of the Bhagavata).

The mind is always accompanied by six enemies—namely, kāma, krodha, mada, moha, mātsarya and bhaya—that is, lust, anger, intoxication, illusion, envy and fear. Although the mind may be merged in spiritual consciousness, one should always be very careful in dealing with it, just as one is careful in dealing with a snake. One should never think that his mind is trained and that he can do whatever he likes. One interested in spiritual life should always engage his mind in the service of the Lord so that the enemies of the mind, who always accompany the mind, will be subdued. If the mind is not engaged in Kṛṣṇa consciousness at every moment, there is a chance that it will give way to its enemies. In this way we become victims of the mind.
(Sri Caitanya Caritamrta--2:11:10---purport).

The ingredients of matter are counted as twenty-three: the total material energy, false ego, sound, touch, form, taste, smell, earth, water, fire, air, sky, eye, ear, nose, tongue, skin, hand, leg, evacuating organ, genitals, speech and mind. All are combined together by the influence of time and are again dissolved in the course of time. Time, therefore, is the energy of the Lord and acts in her own way by the direction of the Lord. This energy is called Kālī and is represented by the dark destructive goddess generally worshiped by persons influenced by the mode of darkness or ignorance in material existence. In the Vedic hymn this process is described as mūla-prakṛtir avikṛtir mahadādyāḥ prakṛti-vikṛtayaḥ sapta ṣoḍaśakas tu vikāro na prakṛtir na vikṛtiḥ puruṣaḥ. The energy which acts as material nature in a combination of twenty-three ingredients is not the final source of creation. The Lord enters into the elements and applies His energy, called Kālī. In all other Vedic scriptures the same principle is accepted.
(Srimad Bhagavatam--3:6:2---purport).