And we cannot speak for God, just be guided by the word. The sins of the Old Testament, are not the same in the New. We can eat a cheeseburger, cook on the Sabbath, and women can wear jeans. Our human nature is the one we struggle with, as we become more spiritual. The human nature can lead us to the sins of Lust, Pride, Envy, Gluttony, Sloth, Avarice, Envy. There are degrees of those, but it is not up to us to say which one is worse, or when the line is crossed, suffice it to say that we all struggle with it, and that Christ knew this, and sacrificed himself so that we could start over. We are allowed to repent and sin no more, but it takes self reflection and guidance to break it down, taking our own inventory. Adultery is a sin in the old testament, in the New, Jesus tells the woman to go and sin no more, but his admonition to those condemning her was the point of that parable. There was one perfect man without sin, and he was crucified.