Frequently, I encounter among readers of the Bible a struggle with whether the Old and New Testaments portray God consistently. The most common sentiment is something like, "God is full of wrath and judgement in the OT and love and mercy in the NT."
The purpose of this post is to offer some helpful guidance in resolving this matter. Please understand that I will not attempt to prove the overall reliability of the Scriptures either historically or theologically. I am assuming that the reader already has a generally high view of the Bible, but still struggles with seeming contradictions or inconsistencies between the Testaments. Second, I will only scratch the surface of this broad subject. Most specifically, my goal is to offer the struggling Christian and genuinely interested skeptic a general summary and one key idea that is often overlooked that perhaps will bring some clarity on this issue.
First, let me offer several general truths offered within the text:
1. God does not change (Malachi 3:6, Hebrews 13:8)
2. All Scripture is inspired by God (1 Timothy 3:16-17)
3. The NT is clear that its events are the fullfillment of Yahweh's plan (the same God written about in the OT)
4. Both the OT and NT present God as merciful and loving.
5. Both the OT and NT present God as the holy judge of sin.
I think many Christians misunderstand the OT largely because they do not read it very often. The OT contains judgement for sure, but we see over and over again that God is merciful and faithful to his people, even when they are unfaithful. Likewise, many people assume that God is only loving and merciful in the NT, overlooking the fact that God is still very serious about sin and will judge every person according to his holy standards.
Finally, we arrive at the question that appears to best most pressing. What is God's plan of salvation? Was it different in the OT than it is in the NT? It is here that we discover what I think is the strongest link between the two Testaments: Justification by Faith!
Wait a second...you might be thinking, "But didn't they have to perform a bunch of sacrifices and rituals in the OT in order to be saved." Well, Yahweh did command these acts of worship and obedience. But, if we look closely we see that God declared Abram righteous on account of his faith (Gen. 15:6). Earlier we see that Abram called on the name of the Lord (Gen. 13:4). Even as early as Gen. 4:26, it is recorded that "At that time men began to call on the name of the Lord." If this sounds familiar, it should because it mirrors the language of Romans 10:13, "Everyone who calls on the name of the Lord will be saved." (quoting Joel 2:32) This was before the sacrifices were institutied, therefore they cannot be required for salvation/righteousness. They were an expression of obedience in response to genuine faith. The same is true for good works in the life of a NT believer. They are not required for salvation, but are the natural outflow of a life of faith in God.
Both the OT and NT tell us of Yahweh, the God of Abraham, Isaac, and Jacob. The same God who became flesh and dwelled among us in the person of Jesus Christ. He can be known by all who seek him in faith. Our relationship with him was broken by the fall of sin, but we can be declared righteous by placing our faith in Him. Trusting in any other source (self, money, false religion, etc.) is idolatry and God will not stand for it. This is the God that we see unfolding His plan to redeem humanity. It reads from Genesis to Revelation. If you don't get it yet, I urge you to continue reading, especially the portions that you are not yet familiar with.
Please feel free to email or comment with questions.