Charles Ellicott Commentary Revelation 2:4

"But I have [this] against thee, that thou didst leave thy first love." — Revelation 2:4 (ASV)

Nevertheless I have somewhat against thee.—Better, I have against you that you did let go. This is the fault, and it is no trifle which is blamed, as the word “somewhat” (which is not to be found in the original) might be taken to imply; for the decay of love is the decay of that without which all other graces are as nothing (1 Corinthians 13:1–3), since “all religion is summed up in one word, Love. God asks this; we cannot give more; He cannot take less” (Norman Macleod, Life, i., p. 324).

Great as the fault is, it is the fault which Love alone would have detected. “Can anyone more touchingly rebuke than by commencing, ‘You no longer love me enough?’” It is the regretful cry of the heavenly Bridegroom, recalling the early days of His Bride’s love, the kindness of her youth, the love of her espousals (Jeremiah 2:2. Compare to Hosea 2:15). It is impossible not to see some reference in this to the language of St. Paul (which must have been familiar to the Ephesian Christians) in Ephesians 5:23-33, where human love is made a type of the divine.