The Lord says very loudly in the last portion of Bhagavad-gītā (18.66):
sarva-dharmān parityajya
mām ekaṁ śaraṇaṁ vraja
ahaṁ tvāṁ sarva-pāpebhyo
mokṣayiṣyāmi mā śucaḥ
"Abandon all varieties of religion and just surrender unto Me. I shall deliver you from all sinful reactions. Do not fear." Thus the Lord takes all responsibility for one who surrenders unto Him, and He indemnifies such a person against all reactions of sins.

Although Arjuna was, for the time being, overwhelmed with false grief due to family affection, he surrendered unto Kṛṣṇa, the supreme spiritual master, as a disciple. This indicated that he would soon be free from the false lamentation resulting from family affection and would be enlightened with perfect knowledge of self-realization, or Kṛṣṇa consciousness, and would then surely fight.
(Bhagavad-Gita-----2:9-----purport).

The jīva soul is struggling very hard on the tree of the material body, but as soon as he agrees to accept the other bird as the supreme spiritual master—as Arjuna agreed to do by voluntary surrender unto Kṛṣṇa for instruction—the subordinate bird immediately becomes free from all lamentations.
(Bhagavad-Gita-----2:22-----purport).

One can attain Kṛṣṇa consciousness or divine life at once, within a second—or one may not attain such a state of life even after millions of births. It is only a matter of understanding and accepting the fact. Khaṭvāṅga Mahārāja attained this state of life just a few minutes before his death, by surrendering unto Kṛṣṇa. Nirvāṇa means ending the process of materialistic life.
(Bhagavad-Gita-----2:72-----purport).

As all surrender unto Me, I reward them accordingly. Everyone follows My path in all respects, O son of Pṛthā.
(Bhagavad-Gita-----4:11-----translation).

Those who have forgotten Kṛṣṇa must certainly be bewildered, but those who are in Kṛṣṇa consciousness are not bewildered at all. It is stated in the Bhagavad-gītā, sarvaṁ jñāna-plavena, jñānāgniḥ sarva-karmāṇi and na hi jñānena sadṛśam. Knowledge is always highly esteemed. And what is that knowledge? Perfect knowledge is achieved when onesurrenders unto Kṛṣṇa, as is said in the Seventh Chapter, 19th verse: bahūnāṁ janmanām ante jñānavān māṁ prapadyate.
(Bhagavad-Gita-----5:16-----purport).

After passing through many, many births, when one perfect in knowledge surrenders unto Kṛṣṇa, or when one attains Kṛṣṇa consciousness, then everything is revealed to him, as everything is revealed by the sun in the daytime. The living entity is bewildered in so many ways. For instance, when he unceremoniously thinks himself God, he actually falls into the last snare of nescience.
(Bhagavad-Gita-----5:16-----purport).

By transcendental knowledge one can remain steady in his convictions, but by mere academic knowledge one can be easily deluded and confused by apparent contradictions. It is the realized soul who is actually self-controlled, because he is surrendered to Kṛṣṇa. He is transcendental because he has nothing to do with mundane scholarship.
(Bhagavad-Gita-----6:8-----purport).

This divine energy of Mine, consisting of the three modes of material nature, is difficult to overcome. But those who have surrendered unto Mecan easily cross beyond it.
(Bhagavad-Gita-----7:14-----translation).

After many births and deaths, he who is actually in knowledge surrenders unto Me, knowing Me to be the cause of all causes and all that is. Such a great soul is very rare.
(Bhagavad-Gita-----7:19-----translation).

The same description of departure and return is quoted by Ācārya Baladeva Vidyābhūṣaṇa from the Chāndogya Upaniṣad (5.10.3-5). Those who are fruitive laborers and philosophical speculators from time immemorial are constantly going and coming. Actually they do not attain ultimate salvation, for they do not surrender to Kṛṣṇa.
(Bhagavad-Gita-----8:26-----purport).

He is the master of the material energy. As has been explained in several places (mama māyā duratyayā), He claims that the material energy, although very powerful, is under His control, and whoever surrenders unto Him can get out of the control of this material energy. If a soul surrendered to Kṛṣṇa can get out of the influence of material energy, then how can the Supreme Lord, who conducts the creation, maintenance and annihilation of the whole cosmic nature, have a material body like us?
(Bhagavad-Gita-----9:11-----purport).

Those who are engaged in fruitive pious activities and who are ultimately hoping to be liberated from this material entanglement will never be successful either, because they deride the Supreme Personality of Godhead, Kṛṣṇa. In other words, persons who mock Kṛṣṇa are to be understood to be demonic or atheistic. As described in the Seventh Chapter of Bhagavad-gītā, such demonic miscreants never surrender to Kṛṣṇa. Therefore their mental speculations to arrive at the Absolute Truth bring them to the false conclusion that the ordinary living entity and Kṛṣṇa are one and the same.
(Bhagavad-Gita-----9:12-----purport).

The Lord says here distinctly, mayi te: "They are in Me." Naturally, as a result, the Lord is also in them. This is reciprocal. This also explains the words ye yathā māṁ prapadyante tāṁs tathaiva bhajāmy aham: "Whoever surrenders unto Me, proportionately I take care of him." This transcendental reciprocation exists because both the Lord and the devotee are conscious.
(Bhagavad-Gita-----9:12-----purport).

When a person comes to full knowledge after many births, he surrenders unto Lord Kṛṣṇa. If one approaches the Godhead by the method mentioned in this verse, he has to control the senses, render service to everyone and engage in the welfare of all beings. It is inferred that one has to approach Lord Kṛṣṇa, otherwise there is no perfect realization. Often there is much penance involved before one fully surrenders unto Him.
(Bhagavad-Gita-----9:29-----purport).

With the association of a bona fide spiritual master, he can see his real position, and by such an understanding he can become fixed in full Kṛṣṇa consciousness. A man in Kṛṣṇa consciousness is not controlled by the spell of the material modes of nature. It has already been stated in the Seventh Chapter that one who has surrendered to Kṛṣṇa is relieved from the activities of material nature. For one who is able to see things as they are, the influence of material nature gradually ceases.
(Bhagavad-Gita-----14:19-----purport).

One who surrenders unto Kṛṣṇa at once surmounts the influence of the modes of material nature. To be in Kṛṣṇa consciousness or in devotional service means to acquire equality with Kṛṣṇa. The Lord says that His nature is eternal, blissful and full of knowledge, and the living entities are part and parcel of the Supreme, as gold particles are part of a gold mine.
(Bhagavad-Gita-----14:26-----purport).

Ahaṁ sarvasya prabhavaḥ: (B.G.10:8) "I am the origin of everything." Therefore to get out of the entanglement of this strong banyan tree of material life, one must surrender to Kṛṣṇa. As soon as one surrenders unto Kṛṣṇa, one becomes detached automatically from this material extension.
(Bhagavad-Gita-----15:3-4-----purport).

He has described in so many ways different types of religion. Now, in summarizing Bhagavad-gītā, the Lord says that Arjuna should give up all the processes that have been explained to him; he should simply surrender to Kṛṣṇa. That surrender will save him from all kinds of sinful reactions, for the Lord personally promises to protect him.
(Bhagavad-Gita-----18:66-----purport).

In the Seventh Chapter it was said that only one who has become free from all sinful reactions can take to the worship of Lord Kṛṣṇa. Thus one may think that unless he is free from all sinful reactions he cannot take to the surrendering process. To such doubts it is here said that even if one is not free from all sinful reactions, simply by the process ofsurrendering to Śrī Kṛṣṇa he is automatically freed. There is no need of strenuous effort to free oneself from sinful reactions. One should unhesitatingly accept Kṛṣṇa as the supreme savior of all living entities. With faith and love, one should surrender unto Him.
(Bhagavad-Gita-----18:66-----purport).

The process of surrender to Kṛṣṇa is described in the Hari-bhakti-vilāsa (11.676):
ānukūlyasya saṅkalpaḥ
prātikūlyasya varjanam
rakṣiṣyatīti viśvāso
goptṛtve varaṇaṁ tathā
ātma-nikṣepa-kārpaṇye
ṣaḍ-vidhā śaraṇāgatiḥ
According to the devotional process, one should simply accept such religious principles that will lead ultimately to the devotional service of the Lord. One may perform a particular occupational duty according to his position in the social order, but if by executing his duty one does not come to the point of Kṛṣṇa consciousness, all his activities are in vain. Anything that does not lead to the perfectional stage of Kṛṣṇa consciousness should be avoided. One should be confident that in all circumstances Kṛṣṇa will protect him from all difficulties.
(Bhagavad-Gita-----18:66-----purport).

There are different processes of religion and purificatory processes by cultivation of knowledge, meditation in the mystic yoga system, etc., but one who surrenders unto Kṛṣṇa does not have to execute so many methods. That simple surrender unto Kṛṣṇa will save him from unnecessarily wasting time. One can thus make all progress at once and be freed from all sinful reactions.
(Bhagavad-Gita-----18:66-----purport).

Karma-yogīs, empiric philosophers, mystics and devotees are all called transcendentalists, but one who is a pure devotee is the best of all. The particular words used here, mā śucaḥ, "Don't fear, don't hesitate, don't worry," are very significant. One may be perplexed as to how one can give up all kinds of religious forms and simply surrender unto Kṛṣṇa, but such worry is useless.
(Bhagavad-Gita-----18:66-----purport).

When a person is in full knowledge, he naturally surrenders to Kṛṣṇa. When Arjuna understood that it was Kṛṣṇa's plan to reduce the unnecessary increase of population, he agreed to fight according to Kṛṣṇa's desire. He again took up his weapons—his arrows and bow—to fight under the order of the Supreme Personality of Godhead.
(Bhagavad-Gita-----18:73-----purport).

There are many mystics and yogīs all over the world, but Kṛṣṇa is the master of all yoga systems. Kṛṣṇa's instruction is explicitly stated in Bhagavad-gītā-surrender unto Kṛṣṇa. One who does so is the topmost yogī. This is confirmed in the last verse of the Sixth Chapter.
(Bhagavad-Gita-----18:75-----purport).

The supreme instruction of morality is stated in the Ninth Chapter, in the thirty-fourth verse: man-manā bhava mad-bhaktaḥ. One must become a devotee of Kṛṣṇa, and the essence of all religion is to surrender unto Kṛṣṇa (sarva-dharmān parityajya mām ekaṁ śaraṇaṁ vraja). The instructions of Bhagavad-gītā constitute the supreme process of religion and of morality. All other processes may be purifying and may lead to this process, but the last instruction of the Gītā is the last word in all morality and religion: surrender unto Kṛṣṇa. This is the verdict of the Eighteenth Chapter.
(Bhagavad-Gita-----18:78-----purport).

From Bhagavad-gītā we can understand that to realize oneself by philosophical speculation and by meditation is one process, but to fully surrender unto Kṛṣṇa is the highest perfection. This is the essence of the teachings of Bhagavad-gītā.
(Bhagavad-Gita-----18:78-----purport).