The short and fast answer is, God. The scripture confirms this interpretation, so let’s go to the Bible.
Our encounter with the concept of good and evil comes to us in Genesis. In Genesis 2, we find a narrative that enlarges on day six of creation (Genesis 1 is the record of creation, days one through seven). Genesis 2:16-17, we find God having conversation with Adam and tells Adam that he may ‘eat freely’ from any tree in the garden EXCEPT for the ‘tree of knowledge of good and evil’. God further states that in doing so would surely bring death.
We must ask ourselves, ‘what does “the knowledge of good and evil” mean’? What does the narrative itself says about the phrase under discussion? First, we are told that knowing good and evil is a characteristic of God (Genesis 3:22). Second, Adam and Eve did not naturally possess this type of knowledge; it was not a deficiency, but simply the way the Lord created them…very good (five times God said his creation was good and then very good in Genesis 1:31). Third, this knowledge leads to the dissolution of the creatures, their return to nothingness, to death (Genesis 2:16-17). Fourth, humans misappropriate this knowledge; they can attempt to break away from the loving limits imposed by the Creator (all have sinned – Romans 3:23-24).
An understanding of the phrase “knowledge of good and evil” needs to be in agreement with the facts recorded for us by the context itself. The entirety of the narrative identifies the meaning and/or significance of the phrase used. The totality of the story makes it crystal clear that to know good and evil is to declare complete and absolute autonomy for our existence; to attempt to remove any sense of answerability to anyone else, including God. It is humans deciding by themselves and for themselves what is good or evil without taking into consideration God’s revealed will.
God is the only absolute autonomous being, not accountable to anyone except to His own character. This type of existence is impossible for us. To be a created being is by definition to be accountable to the Creator. It is the Creator that gives and sustain life, to endeavor to exist in total independence from God would eventually result in extinction. The serpent convinced Adam and Eve that they could open their own eyes and come to know this kind of autonomy while relishing in life apart from God. They could certainly live in rebellion against God, perceiving themselves as unaccountable to Him. This is what the Lord meant when He said that Adam and Eve were “become as one of us, to know good and evil” (Gen. 3:22).
We must not stop here, but also look at this phrase “good and evil” elsewhere in scripture to understand what the biblical writer is communicating. This same phrase is used one other time in the Old Testament in conjunction with the verb “to know,” and it would be good to see whether that usage supports, modifies, or rejects our interpretation.
In Deuteronomy 1:39 we read, “Moreover your little ones, . . . and your children, which in that day had no knowledge between good or evil, they shall go in [to the Promised Land]” (emphasis mine). The phrase in this text is used in a positive way. Children do not know good and evil; they exist in total dependence on their parents; they are not autonomous. As they grow and mature, they will assume responsibility for their own lives, becoming independent of their parents. Even here the phrase expresses or at least implies the ideas of independence and autonomy.
God granted us freedom to choose, but our existence depends on our relationship with Him. To claim autonomy is the same as rejecting the gift of life. The knowledge condemned by God is that which is sought in rejecting or rebelling against His revealed will. To rely on Him in our search for knowledge requires that we become dependent, like children.
His revealed will is to be image bearers, for we were made in His image (Gen. 1:27, James 3:9). Since God is love (1 John 4:8) this is the image we are to live (Deut. 6:4-7, Matt. 22:37-40, Mark 12:30-31, Luke 10:27-28). This is our aim. We must recognize because of sin
We are capable of great empathy and selflessness – and we are also capable of cruelty, hatred, and insensitivity. Why are we like this? We are like this because mankind chose to depart from the will of God and determine for themselves what is good and what is evil. . “…Choose this day whom you will serve” (Joshua 24:15).