In protestantism are all mankind equal under God?

Are there people of higher worth and lower worth? Is everyone deserving of equal respect? There was some confusion in the comments since my question is short, I think the answers given are of good quality. To address the comments, I want to know if people are considered equal to Christians. In contemporary society maybe the answer is an obvious yes and thats where the confusion is coming from? But it was not long ago that people had slaves and many of those slaveowners called themselves Christian, no? So I am asking in a very real and basic sense is it a Christian belief that all mankind are equal? Or maybe some people should be slaves? I don’t know what Christians believe is why I am asking.