Lord Chaitanya, the golden avatar says:
“His entertainment is comparable to the waves of the Ganges, just as the waves of the Ganges break unabated, Lord Krishna, continuously, reveals different aspects and incarnations of his person in different universes.
Krishna remained in our universe for only 125 years, but in each and every universe, He is still manifesting all the entertainment He has performed here; including his apparent birth, his boyish entertainment and his entertainment as a young man. Since the universes are innumerable, his entertainments take place every moment, every second, continuously and without limit. They are therefore presented as eternal.
According to our imperfect vision and our incomplete knowledge, Krishna was born as the son of Devaki and Vasudeva, and after 125 years He disappeared. But the fact is that He exists forever; he simply leaves this world for another. The arrival of Krishna and his departure is comparable to the appearance of the sun in the morning, and its disappearance in the evening. He lives in the company of a mother and a father and "springs forth" from a particular family and place, but He exists eternally, and travels from one universe to another, in order to enjoy relational exchanges filled with happiness with his devotees.
Krishna's entertainment is like a traveling theater show, visiting one planet after another. Krishna does not travel alone. He brings with him his mother, his father, his boy-cowherd friends, the gopis, the cows and the land of Vrindavana. Thus He is never considered to be alone, without His eternal companions and His dwelling place. When He comes down, He goes down with His entourage, and when He travels they all travel with Him.”
Lord Chaitanya, the Golden Avatar, says:
“All of Krishna's Entertainment is similar to the activities of humans, so let's understand that its form is similar to that of man, and the truth is that the human form only imitates Siena. The flute in his hand, Krishna, looks like a shepherd in his early youth, always playful, he amused himself like the common boys.”
When the Lord was present on earth, the beings who were filled in all their material desires by the mere fact of contemplating it in truth, could return with him, in His kingdom. But those who could not see Him as He was, remained attached to their material desires and could not return to the kingdom of God, their original home. And when the Lord disappeared from the sight of all, it is still in its original, eternal form that He did it.
He left this world in his own body. He did not leave his body here below, as the conditioned souls generally believe. God appeared for the sole purpose of relieving the world of the unbelieving burden of unbelievers, and his task accomplished, He simply disappeared from the worldview.