Whatever you offer to Kṛṣṇa or Viṣṇu, that is called sacrifice, yajña. Kṛṣṇa's or Viṣṇu's another name is Yajña-pati. So yajña-śiṣṭāśinaḥ santo mucyante sarva-kilbiṣaiḥ. Whatever we do here within this material world, there is some sort of sinful activity. We do not know, imperceptibly. Just like killing of some animal is sinful activities. But even if we do not willingly kill some animal, when we are walking on the street, we are killing so many animals. When we are drinking water, in the, below the waterpot there are so many ants and microbes, they are being killed. When we ignite fire, there are so many small microbes, they also become burned into the fire. When you rub the pestle and mortar for rubbing spices, so many small microbes are killed. So we are responsible for that. Therefore, willingly or unwillingly, we are becoming entangled in so many sinful activities. Therefore the Bhagavad-gītā says, yajña-śiṣṭāśinaḥ santo mucyante sarva-kilbiṣaiḥ. If you take the remnants of foodstuff of yajña, after offering yajña, then you become free from all contamination. Otherwise, bhuñjate te tv aghaṁ pāpā ye pacanty ātma-kāraṇāt: (BG 3.13) "One who is cooking for eating personally without offering to Kṛṣṇa, he is simply all sinful resultant action." This is our position.
Therefore here it is said that generally persons, adānta-gobhir viśatāṁ tamisram, because they cannot control their senses, adanta... Adanta means uncontrolled; go means senses. Viśatāṁ tamisram. Tamisram means this materialistic way of life, repeated birth and death in different species or forms. That is called tamisram. I do not know what is my next life, but next life is there. And before us there are so many species of life, and I can become one of them. I can become a demigod. I can become a cat. I can become a dog. I can become Brahman. There are so many forms of life. Sarva-yoniṣu kaunteya sambhavanti murtayo yaḥ (BG 14.4). So next life I will have to accept one of the forms even if I do not want. Suppose if somebody says, "Next life, would you like to take the form of a dog or a hog?" I may not like it, but the law of nature, after giving up this body, when no more I am existing in this body, I have to accept another body according to my karma. That is in the hands of nature. Karmaṇā daiva-netreṇa (SB 3.31.1). Daiva-netreṇa, "by superior supervision." You cannot order that "Give me the body of Brahma. Give me the body of Indra or a king or something exalted." That is not in your hand or in my hand. That will be judged by the superior agent of God, Kṛṣṇa, and you will have a body. Therefore it is our duty to prepare a body which will help me to go back to Kṛṣṇa. That is Kṛṣṇa consciousness.