Now we come to the tree of the knowledge of good and evil. We know that the word "knowledge" is derived from the word "know." In Scripture, "know" describes the intimate relationship between a man and a woman, e.g. Adam knew Eve. I don't think I have to go into further detail. What I want to get to: Adam and Eve "knew" only good at their creation; they only had knowledge of good. Look at "fruit" as "fruit of the Spirit." The "fruit" that they had was only good. After their disobedience of God's command, they then "knew" evil, had an intimate relationship with evil. Disobedience is evil; therefore, when they disobeyed, they bore the fruit of evil and they had to die--for disobedience is not of God, is not of His nature. It separated them from God. Now we understand why our Lord Jesus said, "...the things that come out from within are what defile." Disobedience came from inside Adam and Eve and defiled them. Satan, yes, tempted them; but the disobedience came from within and defiled them. "From within the man, from his heart" (mind) "come evil thoughts, unchastity, theft, murder, adultery, greed, malice, deceit, licentiousness, envy blasphemy, arrogance, folly. All these evils come from within and they defile."
Upon our Baptism, we were reunited with God by and through Jesus Christ. We have eaten from the Tree of Goodness, of Righteousness; we "know" goodness, righteousness. If we enjoy sinning, then we must question our love of God. If we love sinning, we love, "know," evil. Yes, it is true that sometimes our passions overwhelm us. Although we have power over our passions, they are still very strong. We can only overpower them sometimes with fasting and prayer. If we fail, we have access to the Sacraments.
If we "know" good, have an intimate relationship with Righteous, we will be in the Garden, the Kingdom; if we "know" disobedience, have an intimate relationship with sin, evil----
This reflection is taken from Wednesday of the Fifth Week in Ordinary Time. See: http://www.usccb.org/bible/readings/021115.cfm