In Episode #11 of the Glory Cloud Podcast, Charles Lee Irons and Chris Caughey discuss Meredith Kline’s understanding of the Covenant of Common Grace. It’s a helpful podcast that I recommend all libertarians listen to as it provides the proper biblical framework for approaching the question of civil government. I also recommend this more in-depth lecture from Irons on the topic.
In the episode, they discuss Kline’s essay The Oracular Origin of the State. Kline argues that God institutes the city-state in Genesis 4 in response to Cain’s complaint. I have to say, I think he rather significantly misinterpreted Genesis 4.
Kline’s thesis is that when Cain complains “whoever finds me will kill me,” he was primarily concerned that he would be executed by vigilantes, rather than by the proper authorities. Thus God assures Cain that only the divinely appointed city-state ruler may execute him as a manifestation of God’s judicial oversight. According to Kline, Cain’s great concern was that his execution would be disorderly, “lawless,” “mindless,” “anarchical terrorism,” and “absolute anarchy” rather than orderly and lawful by a “minister of God” in a city-state. God sympathizes with Cain and institutes the city-state. Thus Genesis 4 should be “Understood as a foundational revelation of the judicial order of the state.” “To Cain, God signified that for mankind in general he would provide in his common grace an institutional agent to bear the sword of his wrath in the temporal course of world history (cf. Rom 13:4).”
That’s obviously not Cain’s concern. And it’s obviously not God’s concern. God does not swear an oath to Cain that he will be executed by the proper authorities once he reaches a city-state. Rather, he says he will not be executed by anyone at all, which is a response to Cain’s complaint that he will be executed. In a footnote, Kline acknowledges “God’s judgment on Cain’s act of murder was, indeed, distinctive in its sentence of exile rather than the death penalty subsequently prescribed for that crime; but that is another matter.” That is not another matter. It is the very matter at hand.
Rather than subjecting Cain to the established justice: execution for murder, God cursed Cain to wander the earth in exile. Normally, Abel’s murder could be avenged by any image bearer, thus God had to let everyone know that the normal procedure does not apply to Cain. He is not to be executed per lex talionis clarified in Genesis 9:6, but is rather to be left a vagabond and exile to wander the earth cursed by the ground.
The consequences of the judicial dereliction Cain anticipates (Gen 4: 14b) will be, he laments, that everyone in the family of mankind, kinsmen all of his innocent victim, Abel, will be let loose in a mindless blood feud to take vengeance on him (v 14d): “Everyone who finds me will kill me.”  Hidden from God’s face, he will have no judge to appeal to. Society east of Eden will be devoid of God’s judicial ordering. Cain will be exposed to lawless men bent on vengeance. He will be ex lex on a God-forsaken earth.
This betrays Kline’s presuppositions, rather than his exegesis. The text says absolutely nothing about such vengeance being “lawless” and “mindless.” In fact, this process of a kinsman executing vengeance upon the murderer was the default, lawful practice under Old Covenant law. Numbers 35 and Deuteronomy 19 explain the role of the avenger of blood (the kinsman of the murder victim, not a state official). Numbers 25:19 says “The avenger of blood himself shall put the murderer to death; when he meets him, he shall put him to death.” This is precisely what Cain was afraid of – his lawful execution. For more on this, see The Avenger of Blood.
Some have found divine warrant for the state in Gen 9:6, where God commands Noah’s family to return bloodshed for bloodshed. But this is a command given to a family. There is no indication of any new institution being established. And in the law of Moses, the execution of murderers was carried out, not by the state as such, but by the “avenger of blood,” kin of the murder victim, Num 35:19, 21; Deut 19:12. The family, here, is the instrument of justice. We have no reason to believe, therefore, that any special institution beyond the family for the establishment of justice was created in Gen 9:6… Was there, at this point in history, also a divinely appointed “state”? I would say no if, again, “state” refers to something above and beyond the natural authority of the family. As far back as Genesis 9, as we have seen, God called the family to execute vengeance for bloodshed, and so no new order was needed to administer capital punishment… Thus I believe we may eliminate from our consideration the views of the Lutherans and Meredith Kline, as well as others, who see the state as a distinct institution ordained by God, with powers and responsibilities different from those of the family.