Good and evil cannot coexist. While the good is happy and willing to tolerate, hoping to lead evil to it’s happiness, the evil is envious of the good’s peace and joy and works to disrupt it. This division has been with us since original sin and before.
Yes, it would have been nice if Adam and Eve had ignored the devils temptation to partake of the forbidden fruit but, in all reality, would it have ended there? I doubt it. The devil is not one to give up. If there is any trace of peace, happiness or joy in our spirit, he will work to destroy it. Division was created the moment Lucifer decided he wanted to be God and rallied a third of the angels to overthrow Him, only to be defeated by St. Michael and the other angels. That did not end the conflict. The devil took it to another level, our humanity, where it will continue until the end of time when God vanquishes him to the netherworld, the emptiness of hate, for all eternity.
Fortunately for us, Jesus, through His baptism of death, has set the earth ablaze with His holy fire which, according to the Ignatius Study Bible has a threefold nature. First, it represents God’s presence in the world and love for us (Deut. 4:24; Acts 2:3). Next, it symbolizes His judgment on sinners (Lev. 10:2; Mt. 22:7). Finally, it signifies Divine purification (Mk. 19:38; 1Pet. 1:7; and CCC 696). All three of these—His loving presence, judgment of sin and His mercy and forgiveness—work to help us win the battle that exists for each of us between good and evil.
“Do you think I have come to establish Peace on earth?” This seems to be in direct conflict with Jesus’ consistent post-resurrection greeting until we remember that His Peace is not as the world gives peace. His Peace is not an end to the conflict, which will cease only at the end of time. His loving presence, judgment, mercy and forgiveness sustain us in the battle and give us power over the forces of evil when we live with Faith, Hope and Charity. It is a Peace beyond all understanding.