The Lord said, "I will never again curse the ground because of humankind, for the inclination of the human heart is evil from youth." - Genesis 8:21
You know that the Son of God was revealed to take away sins. - 1 John 3:5
Two-year reading texts: Psalm 69:13-21; Proverbs 19; 2 Corinthians 2:14-3:11
"Good" and "evil" are categories that appear over and over again in the Bible, but for different writers and in different contexts, the words can mean different things. In some cases, "good" seems to mean something or someone that is aligned with God and God's purposes, while "evil" is aligned against God, sometimes connected with "the devil." In other cases, "good" means something that builds up life and is experienced as pleasant and desirable, while "evil" means something harmful or painful.
There are also differences in how "good" and "evil" are applied. Sometimes they refer to people, sometimes to characteristics of people, sometimes to actions, sometimes to situations.
Both the Genesis 8 and 1 John 3 verses are parts of longer passages about good and evil. The first is part of the story of Noah, as the floodwaters recede after the whole earth is wiped out. Noah and his family emerge and make a sacrifice to God, and God makes a covenant, sealed by the rainbow, to never flood the world again. what God means in Genesis 8:21 is open to interpretation. It's a separate resolution, apparently spoken privately by God "in his heart," referring back to Genesis 3:17, where God cursed the ground due to Adam's sin. It helps to interpret 8:21 by noting that "the ground" is the Hebrew word adamah, "humankind" is the word adam, which is both the name of the first human and the name for humanity in general, and "the human heart" is "the heart of adam." The reason God takes action seems to be that adam's heart, from youth, is evil (ra', meaning rotten, flawed, willful, corrupt, ethically bad). Because of this, God resolves not to curse the adamah again. Why? Because God doesn't need to, since adam/adamah is already cursed? Because adam will curse adamah independently anyway? Because neither adam nor adamah could stand it if another curse were added? In the context of Noah's repentant offering, and God's covenant and restart with humanity, this resolution seems to be an act of grace and mercy. Humankind and the earth are bound together, and because human nature bends toward destruction, God will not add a further curse.
In 1 John 3, today's verse is a testament to the power and purpose of Jesus to remove "sin" (another way to describe the evil of the human heart, bent away from God's life-giving nature toward selfishness and death) from the world. The writer goes on to say that those who abide in Jesus don't sin, and that those who do sin are children of the devil. For a while this sounds like a clean division of humanity between good people and evil people. But then in the last few verses of 1 John (5:16 and following) the writer tells his readers to "give life" to a brother or sister who sins. So there is not such a clear black-and-white between good and evil. In light of the Genesis insights, maybe we can say that without Jesus, the human heart bends toward sin and evil and death and destruction, but with Jesus, there is irrepressible hope for life and the righteousness of alignment with God and God's ways.
It's not hard to find examples from daily life of good and evil, sin and righteousness, life and death, transgression and forgiveness, blessings and curses. And our temptation is always to draw a line between "us" and "them," where we mark "us" as good and "them" as evil.
I think this very kind of line-drawing is an example of the evil of the human heart. We take what is comfortable, easy, pleasant, and beneficial to us, and act as if the whole world is defined around that. We dismiss the rest of God's creation, anything that is inconvenient to us or opposed to our desires, as evil. Yet God is the creator of all things, and all of humankind is made in God's image. We should be more careful with how we use words like "good" and "evil," especially when applying them to people.
In the face of all of this, the presence and purpose of Jesus stand clear. Jesus came because "God so loved the world that he gave his only Son, so that everyone who believes in him may not perish but may have eternal life. Indeed, God did not send the Son into the world to condemn the world, but in order that the world might be saved through him." He came "that they may have life, and have it abundantly." He came "that they may know the only true God." He came to give everything we need for a redeemed life that overcomes the faults of our human heart: "I am the vine, you are the branches. Those who abide in me and I in them bear much fruit, because apart from me you can do nothing." Thanks be to the grace and mercy and love of God, made known and made available to all people in Jesus Christ.