In Acts 15 The Council of Jerusalem lists sexual immorality as one of the things for the gentile believers to avoid.

Hebrews 13:

4 Marriage should be honoured by all, and the marriage bed kept pure, for God will judge the adulterer and all the sexually immoral.

James 1

21Therefore, get rid of all moral filth and the evil that is so prevalent and humbly accept the word planted in you, which can save you.

1 Peter 4

1Therefore, since Christ suffered in his body, arm yourselves also with the same attitude, because he who has suffered in his body is done with sin. 2As a result, he does not live the rest of his earthly life for evil human desires, but rather for the will of God. 3For you have spent enough time in the past doing what pagans choose to do - living in debauchery, lust, drunkenness, orgies, carousing and detestable idolatry.

1 John (perhaps the most ambiguous...)

16For everything in the world - the cravings of sinful man, the lust of his eyes and the boasting of what he has - and does comes not from the Father but from the world.

Jude

4For certain men whose condemnation was written about long ago have secretly slipped in among you. They are godless men, who change the grace of our God into a licence for immorality and deny Jesus Christ our only Sovereign and Lord.

Revelation 2

20 Nevertheless, I have this against you: You tolerate that woman Jezebel, who calls herself a prophetess. By her teaching she misleads my servants into sexual immorality and the eating of food sacrificed to idols.

and perhaps most scarily of all lists the sexually immoral as one of the groups explicitly excluded from the New Jerusalem:

Revelation 22
15 Outside are the dogs, those who practise magic arts, the sexually immoral, the murderers, the idolaters and everyone who loves and practises falsehood.