Am I My Brother's Keeper?

Genesis 4:9. You are probably familiar with the story of Cain and Abel, that Cain murdered his brother and was cursed because he did it. What is interesting in that story is that everything was fine until the Lord rejected Cain's offering. Until his offering was rejected, there is no indication that Cain was an evil person, on the contrary, the very reason Cain was bringing his offering was a good indication that he was trying to please God. See what the Lord tells Him: Genesis 4:7. What does to do well mean? The answer is found in Hebrews 11:4. Abel did his offering by faith, that's why the Lord accepted it: Hebrews 11:6. I've been talking a lot about faith in this blog and this story (Cain and Abel) shows that God required faith since the beginning, actually, the very reason Adam sinned was because he didn't believe in God's words: Genesis 2:16-17. Why am i saying that Adam didn't believe? Because of what James wrote: James 2:20. John the Apostle answered the question "am I my brother's keeper?": 1 John 3:10-12. If we are children of God then we will be our brother's keepers, if we are not our brother's keepers, we are children of the devil! Is John saying that i must love christians (brothers in Christ) only? Of course not! See what Jesus Christ taught: Luke 10:25-37. So, according to the Bible we must be "our brother's keepers".