Q. Why is the God of the Old Testament wrathful but the God of the New Testament loving?
A. This is a common question. It is sometimes used to try to discredit the Bible as presenting two very different Gods at different times in history. The question is, however, based on some misconceptions.
First, we must dismiss the notion that there are two Gods, one in the Old Testament and another in the New Testament. Deuteronomy 6:4 says, "Hear, Israel: the LORD is our God. The LORD is one." Jesus repeated this in Mark 12:29. So, both the Old and New Testaments present one and the same God.
It is also important to see that the Old Testament often steps outside the stereotype people have of the "Old Testament God of wrath" and speaks of his mercy and grace: "The LORD passed by before him, and proclaimed, 'The LORD! the LORD, a merciful and gracious God, slow to anger, and abundant in loving kindness and truth'" (Exodus 34:6; see also Deuteronomy 4:31; 2 Chronicles 30:9; Nehemiah 9:17; and many other Scriptures).
Similarly, the New Testament, although it stresses God's grace, does also speak of His wrath: "For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who suppress the truth in unrighteousness" (Romans 1:18; see also Romans 2:5; Ephesians 5:6; and other Scriptures). Revelation 6:16 depicts even the Lamb of God, Jesus, as having wrath: "They told the mountains and the rocks, 'Fall on us, and hide us from the face of him who sits on the throne, and from the wrath of the Lamb.'"
There is only one God, and the one God has a plan that includes the need for both wrath and grace. Earlier, I quoted Exodus 34:6 to show that the Old Testament speaks of God's mercy and grace. Now read that verse along with verse 7: "The LORD passed by before him, and proclaimed, 'The LORD! the LORD, a merciful and gracious God, slow to anger, and abundant in loving kindness and truth, keeping loving kindness for thousands, forgiving iniquity and disobedience and sin; and that will by no means clear the guilty, visiting the iniquity of the fathers on the children, and on the children’s children, on the third and on the fourth generation.'" Is God a poser? Paul responds:
So then, he has mercy on whom he desires, and he hardens whom he desires. You will say then to me, "Why does he still find fault? For who withstands his will?" But indeed, O man, who are you to reply against God? Will the thing formed ask him who formed it, "Why did you make me like this?" Or hasn't the potter a right over the clay, from the same lump to make one part a vessel for honor, and another for dishonor? What if God, willing to show his wrath, and to make his power known, endured with much patience vessels of wrath made for destruction, and that he might make known the riches of his glory on vessels of mercy, which he prepared beforehand for glory, us, whom he also called, not from the Jews only, but also from the Gentiles?
The difference isn't in God. It is in the people and the covenant. There is only one God, and He does not change. Malachi 3:6 says, "For I, the LORD, don’t change." James 1:17 also expresses God's immutability: "Every good gift and every perfect gift is from above, coming down from the Father of lights, with whom can be no variation, nor turning shadow." Yet, although God doesn't change, He can have different purposes and goals for different people at different times and under different covenants. Yet, these purposes and goals are really just steps in His overall plan to save His people.
The Bible isn't fiction but it certainly is a story. Like a great epic, it has many subplots but only one, overarching main plot. That plot is the fall of man and God's saving him through the sacrificial death of His Son. It is the greatest love story ever told.
One of the most important things to be aware of if you want to understand the overall story or plot of the Bible is to know that man got himself into trouble right from the beginning when he disobeyed God and chose law over grace and thus fell into sin and death.
God had put Adam in the Garden of Eden. It was an idyllic setting, and God told him he could eat from any tree in the garden, except one (Genesis 2:16-17). That one tree was the tree of the knowledge of good and evil. God told Adam not to eat from that tree. The law tells us what is right and what is sin ("through the law comes the knowledge of sin"—Romans 3:20). Thus, the law is the knowledge of good and evil. God told Adam to stay away from that tree because once he gained the knowledge of good and evil, he would sin. In fact, eating from it was itself a sin because God had told him not to do it. And when he sinned, he and his descendants would become subject to death (Romans 5:12-13) because sin works death (Romans 6:23a; 7:5, 8-9).
Adam could have eaten from the tree of life (Genesis 2:9) and freely gained eternal life by grace. Read Genesis 3:22: "The LORD God said, 'Behold, the man has become like one of us, knowing good and evil. Now, lest he reach out his hand, and also take of the tree of life, and eat, and live forever...'" Many theologians have apparently not realized the two implications of Genesis 3:22: 1) eating from the tree of life would have given Adam and Eve eternal life, 2) they never ate from that tree. Instead of choosing life by grace, Adam and Eve chose sin and death by the law.
This, then, was the foundation of this world. It was God's purpose to save people from this world of sin and death through His Son, Jesus Christ. God's overall motive in his dealings with man is love, mercy, and grace. God put man in a beautiful garden and graciously provided all of his needs. It was man who chose law. So God, in essence, said, So you want law, do you? Okay, I'll give you law. At the same time, I will also promise you that I will save from the consequences of the law all who will believe in the coming One, the Anointed, the Messiah, the Christ. I will give this promise to Abraham and repeat it to Isaac and Jacob. But from them, I will also raise up a nation that will be an example for all of what it is like to try to attain righteousness through the law.
So God took the descendents of Abraham, Isaac, and Jacob—the children of Israel—and made a nation out of them. One of those descendants, Moses, was the man through whom He gave them a detailed law so that they could try to attain to His standard of righteousness. God took Israel out of slavery in Egypt, brought them to Mount Sinai, and told them the laws He would expect them to keep. When Moses gave the law to them, they didn't wisely say, We can't do this; be merciful to us. They foolishly said, "All the words which the LORD has spoken will we do" (Exodus 19:8; 24:3, 7). So, again, it was their choice. God put them under the Old Covenant, and it was a disaster. They couldn't do it, and God showed them His wrath for breaking the law. This is where God gets the rap for being wrathful and vengeful. But it was man who asked for it.
Fortunately, the law was only until Jesus Christ. Jesus said that He came to fulfill it: "Don't think that I came to destroy the law or the prophets. I didn't come to destroy, but to fulfill" (Matthew 5:17). He fulfilled the law for us, and, thus, He ended it. Galatians 3:22-25 says,
But the scripture shut up all under sin in order that the promise on the ground of faith in Jesus Christ might be given to those who believe. But before the aforementioned faith came, under law we were constantly being guarded, being shut up with a view to the faith about to be revealed. So that the law became our guardian until Christ, in order that on the grounds of faith we might be justified; but this faith having come, no longer are we under the guardian.
Kenneth S. Wuest, The New Testament: An Expanded Translation
John 1:17 says, "For the law was given through Moses. Grace and truth were realised through Jesus Christ." With the coming of Jesus Christ and with the beginning of the New Covenant at His death, the stress of the Bible changed. It went from showing people the futility of trying to attain righteousness through the law to the sure promise of righteousness through trusting in Jesus Christ alone as Savior. It went from emphasizing God's wrath on a sinful and disobedient people to emphasizing His grace towards believers. But the "New Testament God" is not a different God, nor did God change. He is still wrathful towards disobedient sinners. But His plan is also still the same as it was in the beginning: to graciously save His people through faith in His Son Jesus Christ.
One who believes in the Son has eternal life, but one who disobeys
the Son won't see life, but the wrath of God remains on him.