GOD'S WORD® Translation
You have heard that he let me know this mystery through a revelation. I've already written to you about this briefly.

American Standard Version
how that by revelation was made known unto me the mystery, as I wrote before in few words,

Berean Study Bible
that is, the mystery made known to me by revelation, as I have already written briefly.

Douay-Rheims Bible
How that, according to revelation, the mystery has been made known to me, as I have written above in a few words;

English Revised Version
how that by revelation was made known unto me the mystery, as I wrote afore in few words,

King James Bible
How that by revelation he made known unto me the mystery; (as I wrote afore in few words,

World English Bible
how that by revelation the mystery was made known to me, as I wrote before in few words,

Young's Literal Translation
that by revelation He made known to me the secret, according as I wrote before in few words --

Ephesians 3:3 Additional Translations ...