Christ prepared the members of Smyrna for martyrdom, promising them eternal glory for enduring a relatively short time, looking at things from a hopeful perspective.
When Jesus warns us not to let anyone take our crown, He encourages us to endure over the long-haul and not bask in the glory of a brief, victorious accomplishment.
The Ephesus church effectively battled various heresies, for which Christ commends it. However, the members lost sight of the reason, having left their first love.
Cultural compromise, such as found in Pergamos, brings judgment from Jesus. To those who refuse to compromise their convictions, Christ promises eternal life.
Christ cautions the Pergamos congregation to shun the doctrine of the Nicolaitans. The Church suffers when it harbors those who compromise and offend.
Idolatry is the most frequently committed sin, seen in five commandments. God challenges us to either defend our body of beliefs or drop them in favor of His.