Steadiness means that one should be very determined to make progress in spiritual life. Without such determination, one cannot make tangible progress. And self-control means that one should not accept anything which is detrimental to the path of spiritual progress. One should become accustomed to this and reject anything which is against the path of spiritual progress. This is real renunciation. The senses are so strong that they are always anxious to have sense gratification. One should not cater to these demands, which are not necessary. The senses should only be gratified to keep the body fit so that one can discharge his duty in advancing in spiritual life. The most important and uncontrollable sense is the tongue. If one can control the tongue, then there is every possibility of controlling the other senses. The function of the tongue is to taste and to vibrate. Therefore, by systematic regulation, the tongue should always be engaged in tasting the remnants of foodstuffs offered to Kṛṣṇa and chanting Hare Kṛṣṇa. As far as the eyes are concerned, they should not be allowed to see anything but the beautiful form of Kṛṣṇa. That will control the eyes. Similarly, the ears should be engaged in hearing about Kṛṣṇa and the nose in smelling the flowers offered to Kṛṣṇa. This is the process of devotional service, and it is understood here that Bhagavad-gītā is simply expounding the science of devotional service. Devotional service is the main and sole objective. Unintelligent commentators on the Gītā try to divert the mind of the reader to other subjects, but there is no other subject in Bhagavad-gītā but devotional service.
False ego means accepting this body as oneself. When one understands that he is not his body and is spirit soul, that is real ego. Ego is there. False ego is condemned, but not real ego. In the Vedic literature, it is said: ahaṁ brahmāsmi. I am Brahman, I am spirit. This "I am," the sense of self, also exists in the liberated stage of self-realization. This sense of "I am" is ego, but when the sense of "I am" is applied to this false body, it is false ego. When the sense of self is applied to reality, that is real ego. There are some philosophers who say we should give up our ego, but we cannot give up our ego because ego means identity. We ought, of course, to give up the false identification with the body.