In the sermon of the mount Jesus says this "you have heard but I tell you" stuff which sounds like Jesus is changing or adding stuff to the old testament rules, as if he was correcting something. But this can't be. So what is the correct term? What did Jesus do? Did he add something or only refine something? Because many unbelievers use this to show that Jesus changed something and that he had a different opinion as if Jesus did not agree with Yahwe. And is it true that under the old covenant people were killed for doing works on the sabbath like collecting wood? I don't know but I feel like the old convenant was very strict and not funny at all. I mean where is the mercy in the old covenant and the chance to repent and to be forgiven? I feel like under the old covenant everybody was directly killed.