In the first week of the sermon series on Revelation, the focus is on the letter to the Church of Ephesus and the theme of lost love for Jesus. Pastor Robbie highlights that, despite the church's strong doctrine and endurance in the face of persecution, they have neglected their first love for Christ. He emphasizes the importance of having a genuine relationship with Jesus, which is rooted in love rather than mere religious activity. The message calls for remembrance, repentance, and a return to the passionate faith and love for Jesus that characterized their early experiences.