There is another injunction in the Sermon on the Mount, "Don't take God's name in vain". Yes, we should not take God's Name for the purpose of gaining some end. If we merely wish to serve Godhead and implore Him to receive our services, that would in no way infringe any such rules as were dictated by Christ. He has forbidden us to take God's Name in vain. That is true. We should not ask Him for anything just as we ask our suppliers to furnish things for our use. We have simply to submit. He is the best judge how to look after us. We do not know how good will come to us. We cannot examine the merits and demerits of things by our present acquisitions. It is not possible. We should always be ready to submit to Him unconditionally. All other ideas except this are not regarded as Bhakti by true religionists. In the Gita we find three divisions. The first six chapters are for karmins, the last six chapters are for the Jnaanins and the intermediate six chapters are for bhaktas.

Many people practice tai chi, chi gong, and so on with the aim of keeping their bodies fit for a long time. There is certainly nothing wrong with keeping one's body fit—indeed, it is one of the aims of yoga—but unfortunately, many such people are trying to run away from the inevitable death of the body. Some mystic yogis strive to keep their bodies alive forever—but that is not possible. Even if one was the greatest yogi and could keep his body alive for thousands of years, that still is not forever.
Siddhaswarupanda

So the middle portion is the principal part of the book. The Karmakanda and Jnanankanda are not the real essence of the book, they are but its accessory paraphernalia and not its heart. So bhakti or devotion to Godhead should be the principal object of all religions. Bhakti should be considered nitya, that is permanent and constant. "The Supreme Lord is unconquerable." Our strenuous efforts or empirical knowledge cannot give us the facility of bringing Him within our sense-perception. The devotees have no faith in either of these processes, yet they can, by their devotion, manage to accommodate Him within their hearts. We are to throw off all exertions for acquiring knowledge, and leave aside all our explorations of knowledge. We should not mind giving up all that is not wanted. We need not pose ourselves as intellectual giants. But we should always be energetic in our devotional purpose. We are not to have any confidence in the two systems of karma and jnana, or accept the results derived by these two methods. We should be devotees. Aural reception should be sufficient for our purpose. We should hear from the lips of the adepts who are constantly busy in offering their services to the Absolute. They have the power to guide us into channels leading to the love of the All-Love.