Is God different from Old to New Testament?

Does the Bible show an inconsistency in the way God behaves from the OT to the NT? Marcion thought so, but he also had to edit the NT to get the result he wanted, and that's more or less what Skeptics have to do too. What are some of the charges?

In the OT, God goes around killing everyone who sins. In the NT God offers atonement.

This seems to make one assumption, and forget some things about the NT. The assumption is that death is some sort of permanent end point. But for the consistent theist who believes in an afterlife, it isn't -- death is a transition. And it's just one example of a sort of punishment.

And that's where we get to the forgetfulness: Pull the camera back a bit and make the criteria, "God punishes people who do wrong." And THAT occurs in both the OT and in the NT (try Ananias and Sapphira' Paul's command to eject sinners from the fellowship, and last but not least, the prospect of eternal shame and damnation, which I think even Skeptics would see as worse than death to experience).

At the same time, God also offered atonement opportunities in the OT, and offered repentance to people before they were killed (eg, Noah preached before the Flood; the Canaanites knew how Israel had gotten out of Egypt and knew the invasion was coming). So objections about how God is so much "nicer" in the NT is a matter of failed focus.

At the same time, certain critics also fail here by mixing up NT instructions for relations among persons with OT guidelines of judicial punishment. This is like claiming there is a contradiction between judges who sentence a murderer to prison and the brother of the murder victim extending a hand of forgiveness to the murderer. Salvation remains the same in both Testaments; the fundamental role is loyalty to (faith in) YHWH. In both Testaments we see a client-patron relationship between God and man. In both we see that certain behavior is demanded of those who say they are loyal (and if they are loyal, they will behave).

In the OT, God has all these silly rules about lepers and pigs and stuff. That's not in the NT.

Critics who raise this charge are unaware of the role and nature of ritual purity in the ancient world and the role of the law. The fact is that in the NT, Christians are called to be a people apart from the world just as much as the laws of the OT set Israel apart from its neighbors. The basic principle of separation remains the same; all that changes is how it is implemented.

The only way to argue against this is to do a full historical analysis showing that it would have been better to send Jesus in 1400 BC than in the first century -- and if anyone wants to argue that, I expect them to prove it with a detailed social and historical analysis, not merely say so (especially if they are that sort of Skeptic who objects to believing "stuff from a book that is 2000 years old"; how about we made that 3400 years?).

In the OT, the Messiah is a king who would bring everyone to the promised land, and subdue their enemies and stuff. Jesus didn't do that.

That's the same sort of blockade that no doubt Jews of the first century had, but it comes of misplaced expectations. Jesus IS seen in the NT as a king, just not the sort of Roman-beater that was expected. He did gather True Israel (Rom. 9-11) in a community of faith and now rules over them. The problem with this objection is that it only understands rulership in terms of a political state.

Appeals to the continued existence of Judaism are quite irrelevant, by the way, since modern Judaism is a quite different version derived from rabbis of the third and fourth century. Also, it should be noted that Messianic expectations in Judaism of the first century were not always far afield of what Jesus provided. Some would argue, for example, that Deut. 18:20:

But the prophet, which shall presume to speak a word in my name, which I have not commanded him to speak, or that shall speak in the name of other gods, even that prophet shall die.

...means that it is unfair for God to expect people to respect a prophet like Jesus who died. But if that is so, what of Messianic expectations like this one?

2 Esdr 7.26-30: "For indeed the time will come, when the signs that I have foretold to you will come to pass, that the city that now is not seen shall appear, and the land that now is hidden shall be disclosed. Everyone who has been delivered from the evils that I have foretold shall see my wonders. For my son the Messiah shall be revealed with those who are with him, and those who remain shall rejoice four hundred years. After those years my son the Messiah shall die, and all who draw human breath. Then the world shall be turned back to primeval silence for seven days, as it was at the first beginnings, so that no one shall be left."

As the linked article shows, Messianic expectations were often linked to political expectations, and the idea of a suffering or even dying Messiah was not out of the question. Therefore it is misplaced to suggest that God was in any sense "unfair" on this count.

In the OT, God doesn't encourage missionary activity. In the NT He does.

Really? "I, Yahweh, have called you in righteousness, and will hold your hand, and will keep you, and make you a covenant for the people, as a light for the nations..." (Is. 42:6). And how many times is Israel told that their bad behavior makes YHWH a laughingstock, and how many times are they told that YHWH will show His glory and power to the nations? That's called "spreading the message".

Evangelism was done in the OT by demonstration. The ideal pagan was Namaan, who started respecting the God of Israel when he saw YHWH's power manifested. Israel failed in their efforts to spread the message, but the premise to do so was just as clearly there.

The OT teaches nothing about the afterlife. The NT does.

See our treatment of that here and also here. The overriding principles of honor and shame were the same from the OT to the NT period.

The OT teaches monotheism while the NT teaches the Trinity. No, see here. The OT and the historical background does contain the idea of hypostatic entities, and let's keep in mind that even Jewish scholars are coming to the conclusion now that the OT is not so much monotheistic as it is monolatrous. In addition, monotheism is not unitarianism.

In sum, those who claim a vast difference between the OT and the NT in terms of God's character and action usually commit one or more of these errors: