At surface level the term refers to transgressors of the seventh commandment, those who do not keep themselves chaste within holy marriage. On a deeper level the term refers to people of God who are unfaithful to their spiritual Husband (recall the recent references to Christ Jesus as the husband
and the church as a bride,
Revelation 21:2). Perhaps contrary to their expectations, on the day when Christ comes with his recompense, these Christians
will find themselves outside
(Matthew 7:21). Here is an echo of the warning issued in Revelation 2:15; see also Revelation 9:21.
15 Outside are the dogs and sorcerers and the sexually immoral and murderers and idolaters, and everyone who loves and practices falsehood.