My kid brother died years ago. It was heartbreaking. Unlike Cain, I hadn’t killed my ­brother, but Cain’s question to God exploded in my soul. Suddenly I knew the answer: “Yes, I am my brother’s keeper.” I’d wanted to protect my little brother.

After leaving Eden, Adam and Eve had two sons: Cain, a crop farmer, and Abel, a shepherd. Eventually Cain offered some fruits of the soil to God while Abel offered the choicest parts from the firstborn of his flock. God honored Abel’s gift but not Cain’s. So Cain got angry.

God warned Cain to control his anger, to do what was right, and to prevent sin—lurking at his door—from devouring him (1 Peter 5:8). But instead Cain killed Abel.

“Where’s your brother Abel?” God asks. And Cain unwisely responds, “Am I my brother’s keeper?”

As a Navy chaplain, I learned that shipmates care for one another. That was all God was asking of Cain—like “At the very least, do no harm!” So it should be for us.

Kneel today at the foot of Jesus’ cross, where “God made him who had no sin to be sin for us” (2 Corinthians 5:21), to save us from sin and death. In his strength, we can obey Jesus: love the Lord your God, your neighbor, one another, and even your enemies (Matthew 22:36-40; John 13:34-35; Matthew 5:43-48). We are our brothers’ and sisters’ keepers.