Throughout time and space, different peoples have had different ideas of which acts are moral and which are not. People take the moral instinct, and come to different conclusions.
Romans tended to think that those with power had the right to use it and to not care about the downtrodden. Charity was done to make you look good, not because helping people in and of itself is a good thing. Charity was focused on helping your kin and allies, not human beings because all humans have value.
Jews thought you should help your neighbor, but not all humans on Earth.
Jesus taught that everyone matters.
Jesus appeared to really think that a rich person could not get into Heaven. Modern Christians find excuses to ignore that. Bible scholar Bart Ehrman said that when Jesus said, with God, all things are possible, he meant God could change rich people’s hearts, convincing them to give away their wealth.
Jesus taught that you don’t need atonement to be forgiven. But his followers thought his death was an act of atonement. So, Jesus was crucified partially for teaching that you don’t need atonement, then his followers codified Jesus’s death as an atonement!
The writer of the Book of Revelations was advocating for things that went starkly against what Jesus himself is purported to have said.
One of the reasons Revelations was included in the Bible was because it could be used to argue for the Trinity.
Revelations was written to specific Christians who felt that they were being persecuted by the Roman Empire, and it was promising that the good Christians would triumph and God would punish the persecutors.
Jesus was not mentioned by Greek or Roman sources in the first 100 years. And, his first Greco-Roman reference was a passing reference. Paul also tells us very little about what Jesus specifically said. Our earliest sources are the four gospels. They are not particularly reliable, but that doesn’t mean they are useless. The Gospels are not first-hand testimony, but people reporting hearsay. They couldn’t know Jesus’s exact words.
We can look at which testimony is earlier, whether one seems to be emphasizing a bias or a message rather than just telling us what happened, to what extent different sources agree with each other, and the extent that Jesus is saying something that seems like his followers would not want him to say.
Luke doesn’t see Jesus’s death as a sacrifice so God will forgive humans for their sins, but rather a key example of how sinful humans are–they killed God’s prophet! If you want to be forgiven, you have to turn back to God, but don’t need a sacrifice, according to Luke.
A version of Christian nationalism believes that Christianity is a pro-war religion that supports strong nationalist policies that protect Christianity and what it views as traditional life. It is more focused on defeating the enemy than on love. It is more about militaristic and capitalist ideology, than the words of Jesus in the Bible.