(Prabhupada's lecture - Śrīmad-Bhāgavatam 1.16.20 - Los Angeles, July 10, 1974)
So yajña is required. Human life is meant for performing yajña. Karma, yajñaḥ karma-samudbhavaḥ. In the Bhagavad-gītā it is clearly said. Karma... Karma means activity. There must be activity. It is not that because we are interested in self-realization, in the elevation of the soul to the spiritual world, that does not mean we shall be idle and lazy. No. You cannot be idle and lazy because if you become idle and lazy, you cannot even maintain your body. That is advised in Bhagavad-gītā. You have to become busy and active. That is required. Even if you want to go to heaven, then also you have to become busy and active. If you want to go back to home, back to Godhead, that also will require your business and activity. And if you want to remain here in this material world, that also required.
Activity you cannot stop, but we have to consider the quality of activity. Quality of activity is bhakti. You have to work. You cannot remain inactive or lazy. You have to work. So Kṛṣṇa advises in the Bhagavad-gītā that "Work for Me." That is intelligence. Yat karoṣi yaj juhoṣi yad aśnāsi yat tapasyasi kuruṣva tad mad-arpaṇam [Bg. 9.27]. This is life. Yat karoṣi, whatever you do. Everyone has to do something. Kṛṣṇa says, "Yes, you have to work. But work for Me." Just like Arjuna was advised. He is a military man. He used to fight. His occupation is, when there there is danger he must fight. A kṣatriya, kṣatriya's business is that. So Arjuna was advised that "You fight for Me, not for your sense gratification." That kind of fight and war is not allowed. Only for the satisfaction of the Supreme Lord you can fight.