Rev 2:4-5
"But I have this against you, that you have abandoned the love you had at first. Remember therefore from where you have fallen; repent, and do the works you did at first. If not, I will come to you and remove your lampstand from its place, unless you repent."
Ephesus: orthodox but loveless. The 'first love' (ten agapen sou ten proten) — the initial love for Christ and the brothers. The loss of love is a spiritual fall even with correct doctrine. The remedy: remember, repent, return to the first works.
Rev 2:10
"Do not fear what you are about to suffer. Behold, the devil is about to throw some of you into prison, that you may be tested, and for ten days you will have tribulation. Be faithful unto death, and I will give you the crown of life."
Smyrna: the persecuted church without rebuke. 'Be faithful unto death' (ginou pistos achri thanatou) — not 'until the end of life,' but 'even if it costs your life.' The crown of life (stephanos tes zoes) is the martyr's reward.