SB 1.10.25
yada hy adharmena tamo-dhiyo nrpa
jivanti tatraisa hi sattvatah kila
dhatte bhagam satyam rtam dayam yaso
bhavaya rupani dadhad yuge yuge
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Whenever there are kings and administrators living like animals in the lowest modes of existence, the Lord in His transcendental form manifests His supreme power, the Truth Positive, shows special mercy to the faithful, performs wonderful activities and manifests various transcendental forms as is necessary in different periods and ages.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
As mentioned above, the cosmic creation is the property of the Supreme Lord. This is the basic philosophy of Isopanisad: everything is the property of the Supreme Being. No one should encroach upon the property of the Supreme Lord. One should accept only what is kindly awarded by Him. Therefore, the earth or any other planet or universe is the absolute property of the Lord. The living beings are certainly His parts and parcels, or sons, and thus every one of them has a right to live at the mercy of the Lord to execute his prescribed work. No one, therefore, can encroach upon the right of another individual man or animal without being so sanctioned by the Lord. The king or the administrator is the representative of the Lord to look after the management of the Lord’s will. He must therefore be a recognized person like Maharaja Yudhisthira or Pariksit. Such kings have full responsibility and knowledge from authorities about the administration of the world. But at times, due to the influence of the ignorance mode of material nature (tamo-guna), the lowest of the material modes, kings and administrators come into power without knowledge and responsibility, and such foolish administrators live like animals for the sake of their own personal interest. The result is that the whole atmosphere becomes surcharged with anarchy and vicious elements. Nepotism, bribery, cheating, aggression and, therefore, famine, epidemic, war and similar other disturbing features become prominent in human society. And the devotees of the Lord or the faithful are persecuted by all means. All these symptoms indicate the time of an incarnation of the Lord to reestablish the principles of religion and to vanquish the maladministrators. This is also confirmed in the Bhagavad-gita.
The Lord then appears in His transcendental form without any tinge of material qualities. He descends just to keep the state of His creation in a normal condition. The normal condition is that the Lord has provided each and every planet with all the needs of the native living beings. They can happily live and execute their predestined occupations to attain salvation at the end, following the rules and regulations mentioned in the revealed scriptures. The material world is created to satisfy the whims of the nitya-baddha, or everlasting conditioned souls, just as naughty boys are provided with playing cradles. Otherwise, there was no need of the material world. But when they become intoxicated with the power of material science to exploit the resources unlawfully without the sanction of the Lord, and that also only for sense gratification, there is necessity of the Lord’s incarnation to chastise the rebellious and to protect the faithful.
When He descends, He exhibits superhuman acts just to prove His supreme right, and materialists like Ravana, Hiranyakasipu and Kamsa are sufficiently punished. He acts in a manner which no one can imitate. For example, the Lord, when He appeared as Rama, bridged the Indian Ocean. When He appeared as Krsna, from His very childhood He showed superhuman activities by killing Putana, Aghasura, Sakatasura, Kaliya, etc., and then His maternal uncle Kamsa. When He was at Dvaraka He married 16,108 queens, and all of them were blessed with a sufficient number of children. The sum total of His personal family members amounted to about 100,000, popularly known as the Yadu-vamsa. And again, during His lifetime, He managed to vanquish them all. He is famous as the Govardhana-dhari Hari because He lifted at the age of only seven the hill known as Govardhana. The Lord killed many undesirable kings in His time, and as a ksatriya He fought chivalrously. He is famous as asamordhva, unparalleled. No one is equal to or greater than Him.