Rescuing Revelation - The Wake-Up Call

The impregnable city of Sardis is the historical backdrop to the meaning of John's letter to the church there. He provides a stark wake-up call to address their slumber and challenge their reputation. Similarly, Laodicea's geographical and economic context provides the basis for John's call to the church there to be fit for purpose. How can what the Spirit was saying to these churches be relevant for us today?