Because we suffer on account of sinful activities. And we enjoy by pious activity. That is the law. If you become nicely educated, cultured, then you get good position in the society. But if you are a rascal, then you suffer. Similarly, we are creating our position. But that... That is called karma-bandhana. Karma-bandhana means so long we do not know what is our duty, we create our position differently and therefore sometimes we suffer, sometimes we enjoy. Therefore we must know what is our duty. That we have forgotten. Na te viduḥ svārtha-gatiṁ hi viṣṇum (SB 7.5.31). In this material condition of life we have forgotten what is our actually aim of life. Therefore Kṛṣṇa comes. Yadā yadā hi dharmasya glānir bhavati bhārata, tadātmānaṁ sṛjāmy aham (BG 4.7). Our duty, when we forget our dharma, that is called dharmasya glāniḥ. Dharma is not a religious sentiment. Dharma means our occupational duty, real meaning. I think I have given in Śrīmad-Bhāgavatam. So when we forget our duty, that is called dharmasya glāniḥ. Glāniḥ means deterioration of our real occupational duty.
SB Canto 4
Mukti, or liberation, means becoming free from the results of fruitive activities. As stated in Śrīmad-Bhāgavatam (2.10.6): muktir hitvānyathā-rūpam. Mukti means giving up all other activities and being situated in one's constitutional position (svarupeṇa vyavasthitiḥ). In this conditional state, we are entangled by one fruitive activity after another. Karma-bandhana means "the bonds of fruitive activity." As long as one's mind is absorbed in fruitive activities, he has to manufacture plans for happiness. The bhakti-yoga process is different, for bhakti-yoga means acting according to the order of the supreme authority. When we act under the direction of supreme authority, we do not become entangled by fruitive results. For instance, Arjuna fought because the Supreme Personality of Godhead wanted him to; therefore he was not responsible for the outcome of the fighting. As far as devotional service is concerned, even hearing and chanting is as good as acting with our body, mind and senses. Actually, hearing and chanting are also activities of the senses. When the senses are utilized for one's own sense gratification, they entangle one in karma, but when they are used for the satisfaction of the Lord, they establish one in bhakti.
If one has killed a man, he should be should be hanged—according to the gravity of his sin. So that is showing mercy upon him. But, if he's not killed, then he'll be killed in so many ways. He'll be... Suppose something, some animal, and this man who has killed. He will take another birth and he will slaughter him. There are so many subtle laws. Māṁsa. The word māṁsa, Sanskrit. Mām means "me," and sa means "he." "As I am eating him just now, he will eat me next life." That is called māṁsa. Māṁsa khādati. This is the definition of māṁsa, or flesh. Māṁsa khādati. "As I am eating, enjoying now, palate, eating some animal, so he'll also eat me next life." This is called karma-bandhana. Karma-bandhana means being locked up in one's material activities. Yajñārthe karmaṇaḥ anyatra karma-bandhanaḥ. Yajña, Viṣṇu..., if you act for Kṛṣṇa, beyond this, whatever you act, you'll be under bondage. Just like I'm killing some animal, eating, enjoying, so it is karma-bandhana. I am being locked up with my action so that I shall become again a cow or goat, and this man, this cow and goat will become man, and he will kill me and eat. You believe or not believe—that's a different thing. But these are the Vedic statement. And, practically, we are seeing that life for life. Why? Unless there is some meaning, why this punishment is there? Life for life.