Scripture teaches no dualism, but an antithesis. There are no two primal causes and eternal principles, constantly warring with each other, but God is one. He alone is eternal and the primal cause and there is no other eternal principle or primal cause next to him. Neither is he both good and evil, nor are the principles of good and evil to be traced to his being, for he is a light and there is no darkness in him. But this good and glorious God according to his eternal and sovereign good pleasure wills to reveal his praises, his eternally adorable virtue antithetically, that is, in opposition to darkness. Darkness, evil, sin are not primal principles, eternally coordinate with light, goodness, righteousness, but the former are subservient to the latter, darkness must serve to bring out the glory of the light, the devil serves to enhance the unsearchable riches of God's being and virtues and works.
In the light of this idea of an antithesis we can understand the placing of “the tree of the knowledge of good and evil” in paradise. By means of it, God carries the antithesis into the life and before the consciousness of man, made after his image.
