What is "sin"? Both the Hebrew and Greek words for this word are an archery term meaning "To miss the mark" or specifically in Hebrew "To miss the golden center of the target." We also have to know the Biblical definition of "perfection." That definition is "brought to its end, finished; lacking nothing necessary to completeness."
What is the mark being missed in a sin? It is to violate God's law. If Adam and Eve violated God's law, they sinned. So, perfection has not bearing on sin. Otherwise Jesus' sacrifice would be meaningless. Jesus could have sinned, but chose not to, and died a perfect man. Thus, balance was restored.
What is interesting is that to sin is to violate a law God has given. The question asked by Plato is "Is it pious because the gods say it is or is it pious because it is pious and the gods have told us so?" In other words - Is it good because God says it is good or is it good because it is good and God has told us so?
If it is good because it is good, God is only a messenger, and whether God still exists or not has no bearing on morality. However, if good is good because God says so then good is subjective to God's wants and desires, which means good doesn't exist.
If you walk into a dark room and see a burning candle you have had a subjective experience. If you close you eyes or turn your back on the candle it is still there. Objective things can be experienced through subjectivity. Therefor we can see good or evil and recognize it.