The scale that he said he was going to have his works weighed on is a valid and helpful picture. Though there won't be a physical scale the Bible does speak of God weighing what we do and men will be judged by a record of their works. The key is what will be on the scales. The Biblical concept is that our goodness will be on one side and God's perfection will be on the other side. If we fall short of his perfection (Matthew 5:48), we are condemned.