My views on objective morality

[Angrboda]

If our understanding of God or of morals has changed, then who is to say that they have changed for the better? You're assuming that our understanding has improved. Yet everything has been getting worse since the Fall, why is our understanding any exception? How do you know that your current moral feelings about slavery aren't a misunderstanding rather than an increase in understanding. How do you know you have the best understanding of morals, and that say people in another country who stone people for homosexuality and rape are not superior. How do you decide what is a part of this objective morality?