This never seems to work the other way around.

Atheists never seem to think that something is immoral, convert to Christianity and then discover that it was moral after all.

Here is one thing the Bible claims is moral behaviour. Or is it?

Is it really moral behaviour to give all your money to the poor for example?

Of course, Christians don't HAVE to give all their money to the poor, but that is a different point. Is it morally correct to give all your money to the poor?