Bhagavad-Gita The Song Divine Chapter 4 (stanza 33-42)

Arjun, sacrifice through knowledge, is superior to sacrifice performed with material thins. For all actions without exception culminate in knowledge, O son of Kunti. …………… (33)

Understand the true nature of that knowledge by approaching seers of Truth. If you prostrate at their feet, render them service, and question them with an open and guileless heart, those wise seers of Truth will instruct you in  that knowledge. ….  (34)

Arjun, when you have achieved enlightenment, ignorance will delude you no more. in the light of that knowledge, you will see the entire creation first within your own Self, and then in Me (the Over soul)……. (35)

Even if you were the most sinful of all sinners, this knowledge alone would carry you, like a raft, across all your sins. ……… (36)

For, as the blazing fire reduces the fuel to ashes, Arjun, even so the fire of knowledge turns all actions to ashes. …… (37)

In this world there is no purifier as great as knowledge; he who has attained purity of heart through prolonged practice of karma yoga, automatically sees the light of Truth in the self in course of time. …… (38)

He who has mastered his senses, is exclusively devoted to his practice and is full of faith, attains knowledge; having had the revelation of Truth, he immediately attains supreme peace in the form of God-realization.  …………….. (39)

He who lacks discrimination, is devoid of faith, and is at the same time possessed by doubt, is lost to the spiritual path. For the doubting soul there is neither this world nor the world beyond, nor even happiness. ……………. (40)

Arjun, actions do not bind him who has dedicated all his actions to God according to the spiritual of Karma Yoga, who doubts have been dispelled by wisdom and who is delf-possessed.. ……. (41)

Therefore, Arjun slashing to pieces, with the sword of knowledge, this doubt in your heart, born of ignorance, establish yourself in Karma Yoga in the shape of even-mindedness, and stand up for the fight. …….. (42)

Thus, in the Upanishad sung by the Lord, the Science of Brahma, the scripture of Yoga, the dialogue between Sri Krishna and Arjun, ends the fourth chapter entitled "The Yoga of Knowledge as well as the disciplines of Action and Knowledge,"