I'm of the opinion that preachers should never focus solely on one aspect of the Bible. You can get into too much trouble if you're only looking at certain passages all the time.
People who only preach the law are subject to start believing in a works-based salvation which requires the keeping of the law.
People who only preach grace are subject to start believing that it doesn't matter whether or not we follow God's commandments as long as we're in His good graces.
People who only preach prophecy are subject to start believing that nothing we do here on earth really matters because we'll be spending eternity with God anyway.
People who only preach the Love of God are subject to start believing that God would never punish people with an eternity in hell because a God of love would never do such a thing.
Etc, etc, etc........
God gave us the whole Bible for a reason - for us to read/study/focus on all of it.