Reformation Sunday is for celebrating not just one day memorializing an event 507 years ago. It is a celebration for every day because of our resurrected Jesus who is the truth we still stand on from Scripture alone.
The best way to get at the Gospel in our Amos reading is to connect it to Christ. It is too easy and tempting to associate it with social justice today. Our people will not need much encouragement to go there. What they need is the surprising and salvific connection to Christ