In Genesis 4 we read of the first murder in the Bible. In this story, Cain kills his brother Abel. Michael Horton in the article, “Pelagianism,” comments on this saying,
“Cain murdered Abel because Cain sought to offer God his own sacrifice. The writer to the Hebrews tells us that Abel offered his sacrifice in anticipation of the final sacrifice, the Lamb of God, and did so by faith rather than by works (Heb. 11). However, Cain sought to be justified by his own works. When God accepted Abel instead, Cain became jealous. His hatred for Abel was probably due in part to his own hatred of God for refusing to accept his righteousness.”
As you can see, Abel was killed because of Cain’s uncontrollable jealously and hatred that came forth due to God rejecting his self-generated righteousness.
Several thousand years later, Jesus said the following to the Pharisees in the Gospel of Matthew,
“Therefore I am sending you prophets and sages and teachers. Some of them you will kill and crucify; others you will flog in your synagogues and pursue from town to town. And so upon you will come all the righteous blood that has been shed on earth, from the blood of righteous Abel to the blood of Zechariah son of Berekiah, whom you murdered between the temple and the altar.” (Matt 23:34-35)
Clearly the same spirit of Cain was embodied by the Pharisees who latter went on to kill Jesus.
I have said countless times to my parish, “The Doctrine of Grace and the Theology of the Cross will always result in the wounded getting healed and the self-righteous getting angry.” This is not only true historically and Biblically speaking, it is unfortunately true today; the spirit of Cain lives. It seems that the spirit of Cain rises up to persecute when the Gospel is proclaimed. The reason why it lashes out at those trusting in the Lamb of God is because the old Adam cannot tolerate the Gospel. The old Adam has never liked the Gospel and never will, thus the reason for the attacks.
Martin Luther in his Commentary on Genesis discusses the tragedy between Cain and Abel. In the following section of his commentary he discusses the conflict between Cain and Abel in connection to the church. As you will see, he divides the church into two categories, the Church of Cain and the Church of Abel. Like the thoughts above, Luther fleshes out the idea that the church of Cain will always persecute the Church of Abel. He states,
“Moreover, here the church begins to be divided into two churches: the one which is the church in name but in reality is nothing but a hypocritical and bloodthirsty church; and the other one, which is without influence, forsaken, and exposed to suffering and the cross, and which before the world and in the sight of that hypocritical church is truly Abel, that is, vanity and nothing. For Christ also calls Abel righteous and makes him the beginning of the church of the godly, which will continue until the end (Matt. 23:35). Similarly, Cain is the beginning of the church of the wicked and of the bloodthirsty until the end of the world. Augustine treats this story in a similar way in his book The City of God.
It is both very instructive and very comforting to trace each of the two churches from these men as the originators and to note by what a marvelous plan God has always directed their affairs. At one time the true church was the greater; at another time it was the smaller—yet always in such a manner that the hypocritical and bloodthirsty church enjoyed honor before the world and crucified the church which was the true one and was loved by God. Even then the divine promise began to work itself out, in that the serpent’s seed bit the heel of the blessed Seed (Gen. 3:15), just as we experience today. Therefore this lot should not frighten us. It should rather be a source of comfort for us to learn from experience that we are being dealt with by our adversaries in the way bloodthirsty Cain dealt with righteous Abel.
We today are not the first to whom it happens that we are deprived of the name “church,” that we are called heretics, and that those who kill us pride themselves on being the true and only church and maintain their claim to this name with the sword and with every sort of cruelty. The same thing happened to righteous Abel and also to our Lord Christ, who was not a priest or a king in Jerusalem but was driven to the cross by the priests and rulers. But, as Paul says, we must be conformed to Christ (Rom. 8:29). Therefore the true church is hidden; it is banned; it is regarded as heretical; it is slain. But Cain has a glorious name; he alone has a reputation; he gives promise of great things to come. For this reason his hostile heart impels him to fall upon his brother and slay him.
These things pertain neither to the state nor to the household; they pertain primarily to the church. Abel is slain, not because of his activity in the state or in the household but because of his worship of God. For Cain it is not enough that he is the lord of the house; he also wants to be the Son of God; he wants to be the pope and the father of the church. Therefore he appropriates to himself the right to pass judgment on the sacrifices, and he condemns and slays his brother as a heretic.
Similarly, Christ also foretells that His church will be exposed to sundry dangers and that those who slay the godly will regard themselves as performing a service to God (John 16:2). Accordingly, those who want to be the most saintly are the bane and the persecutors of the church. The true church is not regarded as the church; but, in harmony with the name Abel (who is not only a figure of the true church but its beginning), it is considered so worthless that its slayers believe that God does not care about it. Cain is the lord and ruler who does everything and has the power to do everything.
But this is the offense against which we must contend. We dare not come to believe that we are not the church because our adversaries condemn us with such assurance and pursue us with every kind of cruelty; but we must gain the conviction that the cross and those verdicts are true and infallible signs of the true church, as Ps. 10:14 also indicates. Also Ps. 72:14: “Their blood will be regarded precious in His sight,” and Ps. 116:15: “Precious in the sight of the Lord is the death of His saints.” In these passages you hear that when people are slain in this manner, this does not mean that they are of no concern to God, but that this death is precious in the sight of God. Therefore they are truly the people of God, on whom God bestows His care.
Let us, therefore, endure the cruelty of our adversaries and joyfully give thanks to God that we are not among the number of those who kill and, under the pretense of being the church, fall upon and seize the possessions of others and give vent to their cruel fury also on their bodies. For the history of every age bears witness to this: that the true church always endured hardships; but that it was the false church which carried on persecutions, while the true church was always condemned by that other hypocritical one. Therefore there is no doubt among us today that the church of the pope is the church of Cain. We, however, are the true church. Just as Abel did no harm to Cain, so we, too, not only do no harm to them but allow ourselves to be harassed, condemned, and slain by the pope’s church.
Nor are these statements contrary to the truth. It is known to the entire world how often we were excommunicated, harassed by being declared outlaws, and found guilty by sundry verdicts. Nor was there in almost any region of Europe any lack of those who proved themselves passionate executors of the cruel sentences. Spain, France, England, Belgium, Bohemia, Poland, Hungary, Austria, and Bavaria were not exempt from this cruelty and unrighteous fury. Yet what else did they persecute except the doctrine which is godly and in agreement with the writings of the apostles and the prophets? The verdict as to which is the true church cannot be uncertain, can it? You are not of the opinion, are you, that the church is there where no sound doctrine is to be found, where an unjust tyranny is exerted and very great power is linked with wealth? Or is the church rather to be found where there is doctrine beneficial to consciences and where, on account of this doctrine, there are the cross, contempt, poverty, shame, etc., which the small flock of the godly always endured, as history records?” 
God’s grace and peace to you in Jesus name, knowing that your wounds are buried deeply in the wounds of Jesus.
 Luther, M. (1999). Luther’s works, vol. 1: Lectures on Genesis: Chapters 1-5 (J. J. Pelikan, H. C. Oswald & H. T. Lehmann, Ed.) (Ge 4:4). Saint Louis: Concordia Publishing House.