I appreciated these comments by Iain Provan about Cain’s shameless question, “Am I my brother’s keeper?” (Genesis 4:9). Provan notes:
The question is never explicitly answered, because it does not need to be. From the perspective of biblical faith, the answer is obvious. Yes, if you have been created to work the garden and take care of it (literally to “keep” it, Hebrew shamar; Genesis 2:15), you are certainly also to “keep” (shamar) your brother. Just as the good God “will keep you [shamar] from all harm — he will watch over [shamar] your life” (Psalm 121:7), so also a righteous image bearer of God will watch over the life of his fellow image bearer. That is the core of right relating to my various neighbors: to “keep” them.
What is amazing about the story of Cain and Abel is that God continues to “keep” Cain even though Cain did not “keep” his brother. Instead of putting Cain to death, God sends him into exile with the promise that he won’t be overtaken by bloodshed (Genesis 4:14-15), the very blessing that Cain denied to Abel. God watches over and protects Cain even though Cain does not deserve it.
If neighbor-keeping is being “like God” and reflecting his image and imitating the way he keeps people, then we should think about the way God treats Cain. It teaches us that we are to be our neighbor’s keeper even when they don’t deserve it, even when they’ve acted like an enemy, even when they can’t see their own hypocrisy (after all, what is more hypocritical than Cain complaining to God that someone might kill him?). God’s “keeping” is always rooted in grace and not in the worthiness of the recipient of his care.