We never see a picture of Kṛṣṇa in old age because He never grows old like us, although He is the oldest person in the whole creation—past, present, and future. Neither His body nor His intelligence ever deteriorates or changes. Therefore, it is clear that in spite of His being in the material world, He is the same unborn, eternal form of bliss and knowledge, changeless in His transcendental body and intelligence. Factually, His appearance and disappearance are like the sun's rising, moving before us, and then disappearing from our eyesight.
(BHAGAVAD-GITA-------4:6--------PURPORT).

Kṛṣṇa appears and disappears in innumerable universes, just as the sun appears and disappears during the day. Although the sun appears to rise and set, it is continuously shining somewhere on the earth. Similarly, although Kṛṣṇa's pastimes seem to appear and disappear, they are continuously existing in one brahmāṇḍa (universe) or another. Thus all of Kṛṣṇa's līlās are present simultaneously throughout the innumerable universes. By our limited senses we cannot appreciate this; therefore Kṛṣṇa's eternal pastimes are very difficult for us to understand.
(SRI CAITANYA CARITAMRTA------2:20:397--------PURPORT).

And because Lord Kṛṣṇa's appearance and disappearance are completely different from that of any ordinary, common living entity, it is evident that He is eternal, blissful knowledge by His internal potency—and He is never contaminated by material nature. The Vedas also confirm that the Supreme Personality of Godhead is unborn yet He still appears to take His birth in multimanifestations. The Vedic supplementary literatures also confirm that even though the Lord appears to be taking His birth, He is still without change of body.
(BHAGAVAD-GITA-------4:6--------PURPORT).

Nārada replied, "My dear Lord, this kind of behavior by Your Lordship is not at all astonishing, for You are the Supreme Personality of Godhead and master of all species of living entities. You are the supreme friend of all living entities, but at the same time You are the supreme chastiser of the miscreants and the envious. I know that Your Lordship has descended to this earth for the proper maintenance of the whole universe. Your appearance, therefore, is not forced by any other agency. By Your sweet will only, You agree to appear and disappear. It is my great fortune that I have been able to see Your lotus feet today. Anyone who becomes attached to Your lotus feet is elevated to the supreme position of neutrality and is uncontaminated by the material modes of nature."
(KRSNA BOOK).

The Supreme has nothing to do, but because He is omnipotent, everything is performed by Him naturally, as if done automatically. As a matter of fact, the appearance and disappearance of the Supreme Personality of Godhead and His different activities are all confidential, even to the Vedic literatures. Yet they are displayed by the Lord to bestow mercy upon the conditioned souls. We should always take advantage of the narrations of the activities of the Lord, which are meditations on Brahman in the most convenient and palatable form.
(SRIMAD BHAGAVATAM--------1:3:35--------PURPORT).

The Personality of Godhead and His liberated devotees like Nārada appear in the material world by the same process. As it is said in the Bhagavad-gītā, the birth and activities of the Lord are all transcendental. Therefore, according to authorized opinion, the birth of Nārada as the son of Brahmā is also a transcendental pastime. His appearance and disappearance are practically on the same level as that of the Lord. The Lord and His devotees are therefore simultaneously one and different as spiritual entities. They belong to the same category of transcendence.
(SRIMAD BHAGAVATAM--------1:6:29--------PURPORT).

The Supreme Personality of Godhead has no direct connection with material activities. All His acts and deeds, which are exhibited even in this material world, are spiritual and without affection for the modes of material nature. In the Bhagavad-gītā the Lord says that all His acts, even His appearance and disappearance in and out of the material world, are transcendental, and one who knows this perfectly shall not take his birth again in this material world, but will go back to Godhead.
(SRIMAD BHAGAVATAM--------1:8:27--------PURPORT).

The transcendental bodily expansions manifested by the Lord for His pastimes in the mortal world, and the appearance and disappearance of such transcendental expansions, are difficult subject matters, and those who are not devotees are advised not to discuss the Lord's appearance and disappearance, lest they commit further offenses at the lotus feet of the Lord. The more they discuss the transcendental appearance and disappearance of the Lord in the asuric spirit, the more they enter into the darkest region of hell, as stated in Bhagavad-gītā (16.20).
(SRIMAD BHAGAVATAM--------3:4:34--------PURPORT).

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