gitam bhagavata jnanam
yat tat sangrama-murdhani
punar adhyagamat prabhuh
gitam—instructed; bhagavata—by the Personality of Godhead; jnanam—transcendental knowledge; yat—which; tat—that; sangrama-murdhani—in the midst of battle; kala-karma—time and actions; tamah-ruddham—enwrapped by such darkness; punah adhyagamat—revived them again; prabhuh—the lord of his senses.
Because of the Lord's pastimes and activities and because of His absence, it appeared that Arjuna forgot the instructions left by the Personality of Godhead. But factually this was not the case, and again he became lord of his senses.
A conditioned soul is enwrapped in his fruitive activities by the force of eternal time. But the Supreme Lord, when He incarnates on the earth, is not influenced by kala, or the material conception of past, present and future. The activities of the Lord are eternal, and they are manifestations of His atma-maya, or internal potency. All pastimes or activities of the Lord are spiritual in nature, but to the laymen they appear to be on the same level with material activities. It so appeared that Arjuna and the Lord were engaged in the Battle of Kuruksetra as the other party was also engaged, but factually the Lord was executing His mission of incarnation and association with His eternal friend Arjuna. Therefore such apparently material activities of Arjuna did not drive him away from his transcendental position, but on the contrary revived his consciousness of the songs of the Lord, as He sang them personally. This revival of consciousness is assured by the Lord in the Bhagavad-gita (18.65) as follows:
One should think of the Lord always; the mind should not forget Him. One should become a devotee of the Lord and offer obeisances unto Him. One who lives in that fashion becomes undoubtedly endowed with the blessing of the Lord by achieving the shelter of His lotus feet. There is nothing to doubt about this eternal truth. Because Arjuna was His confidential friend, the secret was disclosed to him.
Arjuna had no desire to fight with his relatives, but he fought for the mission of the Lord. He was always engaged in the execution of His mission only, and therefore after the Lord's departure he remained in the same transcendental position, even though it appeared that he forgot all the instructions of the Bhagavad-gita. One should, therefore, adjust the activities of life in pace with the mission of the Lord, and by doing this one is sure to return back home, back to Godhead. This is the highest perfection of life.
Link to this page: https://prabhupadabooks.com/sb/1/15/30