Why is Krishna always naughty? Shouldn't God be good?
We should know, when discussing God, that He's always good; He's absolute and supreme. He may do as He likes, and there's no sin on His part. He's above our limited ideas of "good" or "bad." He's the supremely benevolent Lord, and His actions always benefit everyone, despite our inability to always understand how this is true.
God is great, but we're infinitesimal. For us to judge God by the laws of this limited material world would be a mistake.
Krishna often does things that appear mischievous from our tiny, materialistic point of view. But when the same activities are understood in the light of His being supreme—in other words, seen in the light of scriptural knowledge—then we can understand that everything He does is good for everyone.
- Srimad-Bhagavatam, 10.8.31, Purport:
"Krishna's business in the neighborhood was not only to steal but sometimes to pass stool and urine in a neat, clean house. When caught by the master of the house, Krishna would chastise him, saying, "You are a thief." Aside from being a thief in His childhood affairs, Krishna acted as an expert thief when He was young by attracting young girls and enjoying them in the rasa dance. This is Krishna's business. He is also violent, as the killer of many demons. Although mundane people like nonviolence and other such brilliant qualities, God, the Absolute Truth, being always the same, is good in any activities, even so-called immoral activities like stealing, killing and violence. Krishna is always pure, and He is always the Supreme Absolute Truth. Krishna may do anything supposedly abominable in material life, yet still He is attractive. Therefore His name is Krishna, meaning "all-attractive." This is the platform on which transcendental loving affairs and service are exchanged."
Chaitanya Charitamrita, 4.134, Purport:
"Since Krishna is the Absolute Truth, there are no mundane distinctions such as moral and immoral. Whatever He does is good. This is the real meaning of “God is good.” He is good in all circumstances because He is transcendental, outside the jurisdiction of this material world. Therefore, Krishna can be understood only by those who are already living in the spiritual world."
- Srila Prabhupada once said that while we may become infected in a filthy place, the sun never does. Rather, the sun sterilizes infected places. The sun isn't infected by the urinal water it absorbs; the sun sterilizes it. Similarly, the Supreme Lord can do anything—that's the meaning of "all-powerful"—but He's not affected. He can't do anything sinful. God is always good. We shouldn't think we're equal to God. If, by our limited calculation or social point of view, it appears that God is doing something sinful, it's not sinful. It is sterilizing.
(From a Srimad-Bhagavatam lecture on 7.9.32, given in Mayapur, India on March 10, 1976)