To hearken is to listen attentively, intending to act on what you hear. To search is to proactively seek understanding. In the preface to the Doctrine and Covenants, the Lord invites us to do both. Good disciples are good listeners and good seekers.
Ether and the Books of Kings
Ether has a lot in common with the books of 1 & 2 Kings in the Old Testament: In both accounts, we see the effects of a leader's character on their nation. Prophets deliver warnings boldly. They are not afraid to share the truth, even when it's unpopular.
Biblical Bookends in the Book of Ether
A key message of the Book of Mormon is that we should study the Bible. The book of Ether underscores this point by referencing the first book, Genesis (the tower of Babel), and the last book, Revelation (in conjunction with the brother of Jared's vision).
Searching
We normally "search" for something in particular. But the Savior's instruction to "search the prophets," may have a more general meaning. We may benefit from simply asking what the prophets were trying to say and what their messages mean for us.
A Lying Spirit
The prophet Micaiah told Ahab that his false prophets were filled with a lying spirit. Alma used the same phrase to describe Korihor. Many people choose to say whatever benefits them personally. We should listen to people who are willing to tell the truth
The Immediate Goodness of God
Both Limhi and Alma learned by experience that God can deliver us from the challenges we face. They also learned that that He will provide immediate blessings and strength to help us endure the challenge until the deliverance comes.
Land of Promise, Land of Liberty
Lehi told his sons that their new land of promise was a land of liberty, and that they would be free as long as they remained righteous. Freedom doesn't mean absolution from accountability. It means autonomy within the constraints of the law.