I know: This repeated refrain (Revelation 2:9, 13, 19; 3:1, 8, 15) shows Christ knows everything about his people, their actions, and their situations.
The Ephesian Christians had a correct understanding of their beliefs, marked by perseverance and faithfulness. They examined various claims, disciplined evil people, could tell what is true and false, and patiently suffered for their faith in Christ.