Having sex outside of a God-approved marriage is called fornication: “Nevertheless, to avoid fornication, let every man have his own wife, and let every woman have her own husband” (1 Corinthians 7:2). The Bible plainly says that those who commit fornication without repenting and becoming faithful to God will not be going to Heaven: “Now the works of the flesh are manifest, which are these…fornication…of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God” (Galatians 5:19-21; cf. Matthew 5:31-32; 19:3-12; Acts 2:38; 1 Corinthians 6:9-11; Hebrews 12:14-17; 13:4; 1 John 1:6–2:6).