For a long time, there has been a misconception that God is presented differently in the Old and New Testament. There have been many people who wrongly assumed that God's temperament is different in each section of the Bible. When one closely examines the scriptures, one will find that God is exactly the same. God is equally as holy, righteous, just, gracious and merciful in the Old Testament as well as the New Testament. The Bible even illustrates that the manner in which one should aim to please God is the same in the Old Testament as the in the New Testament - by faith. For example, in Genesis 4:1-16 the Bible presents the testimony of Cain and Abel. Genesis 4:1-16 states that God showed mercy to Eve by getting her through childbirth, so that she gave birth to two sons. It is likely that she had more children as well, but Genesis 4:1-16 documents the interaction between Cain and Abel.
In this portion of scripture, the Bible explains that Cain became a cultivator of the ground while Abel became a shepherd of the flock. Genesis 4:1-16 explains that over time, each presented an offering to the Lord that was related to each one's profession. Since Cain was a farmer of sorts, Cain's offering consisted of some of his produce. Since Abel was a shepherd, the Bible says that Abel gave of the firstborn of his flock. While both gave offerings, the Bible is clear to show that God was only pleased with one of the offerings - Abel's.
Many people have speculated on why God appreciated Abel's offering more than Cain's. Some people teach that Cain's was inferior because it was of the efforts of his own hands. Since Cain was a farmer, the crops represented the results of his own work, which was corrupt from the curse of sin. Some people teach that Cain's offering was lesser in value simply because it came from the ground of the earth that was cursed. There are also some people who teach that Cain's offering was not appreciated because of Cain's attitude. Genesis 4:1-16 goes on to show that Cain was jealous of his brother's offering, and so some teach that this bitter heart corrupted his gift.
While there may be some truth to each of these beliefs, the Bible explains clearly why Abel's sacrifice was accepted over Cain's. In Hebrews chapter 11, the author of Hebrews states that the difference between Cain and Abel's offerings was that Abel's was given "in faith." The type of offering that Abel gave demonstrates faith. In the Book of Hebrews, the author explains God's work process to use the animal sacrifice system to present foreshadowing pictures of the complete work that Jesus would do as the Messiah in order to show that salvation comes by faith, and not by sacrifice. The author of Hebrews uses Abel as an example. Thus, the context of Hebrews shows that Abel's offering was greater than Cain's because it was a foreshadowing picture of the Law, which was in turn a foreshadowing picture of Jesus' death. Abel's offering required the blood of the firstborn, which resembled the instructions of God's Law that was given to Moses. Since Genesis 3:21 showed God slaughtering an animal to cover over the shame of sin, Abel is seen following the example of God rather than developing his own ways to please God. Thus, Abel's sacrifice is given in faith because it followed the example of God, which required blood, which served as a foreshadowing picture of the work of Christ.
Genesis 4:1-16 goes on to explain that as Cain was jealous of his brother's acceptance by God, the Lord approached Cain. God asked Cain why his attitude was poor and spoke sense into Cain. God told Cain that if he was bitter about Abel's sacrifice, then he should simply change the manner of his own sacrifice. God told Cain to repent. God told Cain that if he wanted to be accepted like Abel was, all he had to do was give an offering in the manner that God desired - not his own way. God warned Cain and told him that "sin was crouching at the door." God emphasized how important repentance was. The same sin that caused Adam and Eve to be removed from the Garden, and caused death to rule in the world, was crouching at the door of Cain's heart, waiting for an opportunity to destroy. This is how sin works. Genesis 4:1-16 explains that sin desires us in order to destroy us. Jealousy and a bitter attitude was creating an opportunity for greater danger. God could see into the heart of Cain and tried to warn him, showing that God is patient. Though it says in the New Testament that God is not willing that any should perish, but that all should come to repentance (2 Peter 3:9), the Old Testament shows God's conduct demonstrating that truth about God.
Unfortunately, Cain did not heed the wisdom of God. Cain did not repent and so had to suffer great consequence. Since Cain did not repent, Genesis 4:1-16 shows that his jealousy led to murder. Cain killed his own brother Abel. The Bible often shows that when people live outside of faith, not seeking to do the things that please God, but instead seek to please themselves by their own methods, destruction inevitably arrives. The Bible again demonstrates the patience, mercy, and justice of God. Genesis 4:1-16 explains that God asked Cain about Abel's death and gave Cain an opportunity to confess his sin and repent just like He did with Adam and Eve. However, following the example of his parents, Cain did not confess his sin, and thus paid a terrible consequence. God always gives an opportunity for repentance in order to receive His mercy and grace. Yet, because God is a righteous Judge, when a person rejects His grace and mercy, there is consequence.
The Bible shows that God cursed Cain and removed him from the land, causing him to roam the earth without direction and rest. This is the consequence of sin. Those who reject the offer of God's mercy and grace are often those who wander around in life, unable to find peace, contentment, and rest. They are unsettled in life and tossed about by life's circumstances. Genesis 4:1-16 shows that Cain acknowledged that his judgment would result in a great amount of distance between him and God. This is the result of all sin. Sin causes distances between mankind and God, and without repentance, the distance becomes very dark and desolate. The Bible shows that God marked Cain so that no one would kill him and that God's total judgment against Cain would be fulfilled. In contrast, Genesis 4:1-16 explains that God knew about Abel's death because He heard Abel's "blood cry out from the ground." Cain was judged for his lacking of faith, which led to jealousy, bitterness, and ultimately murder. In contrast, Abel is said to possess qualities of life even after death. His blood is able to cry out. The Book of Hebrews explains that Abel's life cries out still. The faith of Able allowed him to possess qualities that resemble eternal life.
Even before Jesus, the Bible explains that faith in Him is the only way to please God, and the affects of faith are eternal life. The only difference between the Old and New Testament is that God simplified faith by giving the world an object to focus on in terms of faith - Jesus. Yet, as the Bible explains that Jesus is God, and God is Jesus, the object of faith has never really changed either. Praise God!