Later—much later—God would tell Noah that a new covenant was being instituted, one in which life must be given for life taken. He said, “Only, you shall not eat flesh with its life, that is, its blood. For your own lifeblood I will surely require a reckoning: from every animal I will require it and from human beings, each one for the blood of another, I will require a reckoning for human life.

Whoever sheds the blood of a human,
by a human shall that person’s blood be shed;
for in his own image
God made humankind.”[1]

But in these early, antediluvian beginnings, God did not take Cain’s life. What God took was Cain’s means of livelihood, for even against the cursed earth, Cain had proven himself an able farmer, a man of the soil, who found great pride and satisfaction in his work. But now, now that he had poured the blood of his brother out in his field, Cain had polluted forever the very place where before he had found life.
God cursed him in the area of his strength, which now had become the arena of his sin. The ground had already been cursed on account of Adam; now Cain was cursed from the ground, and the dark circle was made complete. The earth would no longer release its fruitfulness to him. For Adam farming was difficult; for Cain it would be impossible. He would be forced to wander from place to place as the crops failed wherever he went, unable to bring forth life.
The penalty for sin is far reaching. Sin can rupture every relationship, becoming the source of untold harm both to ourselves and to others, between ourselves and God, with the power to wrench every good thing within us into ruin.
The extent to which sin had already consumed Cain is seen in how self-centered his response was to God’s justice – complaining, maybe even blaming God for the whole situation. In a spirit of bitterness, he thought God was being overly severe, “My punishment is greater than I can bear! Today you have driven me away from the soil, and I shall be hidden from your face; I shall be a fugitive and a wanderer on the earth, and anyone who meets me may kill me.”[2]
Of course, it makes sense Cain would be afraid of the very evil he had released into the world. There is no indication Cain felt any reproach, any sorrow, any guilt or shame, for the murder of his brother; only regret that God would now mete out consequences. Cain deserved death for taking a life. But, even though his punishment was less than he deserved, he still moaned bitterly about the suffering he imagined it would bring.
Cain was afraid other people would treat him as he had treated Abel. Either his brothers would take vengeance, a life for a life, or he would be killed for being such an obvious outcast, not favored by God, so odious even the ground would now reject him.
God reassured Cain that while human life meant little to him, God valued it highly, and vengeance belonged solely to the Lord. Note that God did not speak to Cain, but to whoever else was there at that point. It was still a small community. Cain and Abel were notable figures among the brothers and sisters, for they had come first. Cain, especially, was the one Eve seemed always to have honored. As the firstborn, the promised son of her seed, the little man God had enabled her to bring forth, Cain would have held an exalted position. He was the crown prince of all humanity, the one who would lead the next generation.
With Cain and Abel absent for this extended time, it is certain the rest of the family would have noticed them missing. “Where is Cain,” they would have asked. “And Abel! Now that you mention it, where is Abel?” Imagine the extended family beginning to gather, especially at the sound of God’s voice.
First one or two, then those few running to bring back more, until all would have been assembled, listening with a growing sense dread as the sickening tale unfolded. Would they have drawn back in horror, and looked on with repugnance as the mark of God grew dark on Cain’s ashen face? The Bible does not say what form of imprint it was, it could have been a visible stamp, or scar, or it may have been some kind of event that confirmed to Cain, and all those gathered, God would not allow others to harm him.
Either way, God made His point clear: even the guilty belong to God. The Lord drew a circle of protective love around Cain and said “Yes, he is guilty. He’s a murderer ‑‑ but he is still Mine. Do not forget My love for him in your dealings with Cain.”
Cain’s mark was not so much the stain of shame, branded in the eyes of others as a terrible murderer. It was more a seal of grace, as one protected by God, a mark of God’s longsuffering love towards him, giving Cain time to think and to repent. While there is life there is hope, God extends mercy and an invitation to everyone, even Cain.
God had first appealed to Cain’s conscience with a question about his feelings. God promised He would accept Cain if only he would do what he already knew was right. God had shown Cain the root of his problem was a sense of entitlement, and jealousy of his brother, that confessing his resentment and envy would set him free from its power. Otherwise, God had told Cain, he would reach a point of no return.
God could have prevented Cain’s crimes, but what God wanted was the development of his character, which only happens when God permits the exercise of human free will, to make moral choices. Conviction is not a pleasant feeling, that unmistakable sense that we have done wrong, but it is a gift from God.
 
[1] Genesis 9:4-6 (NRSV)
[2] Genesis 13-14 (NRSV)
[3] Genesis 9:4-6 (NRSV)
[Image courtesy of Pxhere]