The devil's mistake is often our own. He thought Jesus would be most concerned about physical suffering and self-preservation. That is because that is how he thinks. We make the same mistake in thinking God is like us, that He wants physical things or actions when what He desires is our hearts. We think God will just overlook sin, because that is what we in our weakness tend to do. But God is holy. We must understand God from Scripture and never think He is like us (Psalm 50:21). We are made in His image, but that doesn't mean we should think of Him in our fallen image.