Note 1 at 1Co 5:1: Paul had not heard about this instance of incest through just one witness. This was common knowledge among the believers in Corinth. Even the non-Christians ("Gentiles") didn't live in this kind of sin.

The sin in itself was terrible, but Paul was as upset at the seeming indifference of the other believers (1Co 5:2) as he was with the man who committed the act. This is clearly seen in Paul's statement in 2Co 7:12. There Paul said he wrote about this incident, not for the sake of him that had done the wrong, but so that Paul's care for the members of the Corinthian church would be evident.

Therefore, these instructions about church discipline are as necessary for the body as a whole as they are for an individual member who may fall under this judgment. Those who think it would be terrible to punish a fellow believer as Paul instructs here are failing to see the whole picture. Failure to uphold the Bible's standards of morality will infect the whole body of believers in a similar way that a little yeast will leaven a whole loaf of bread (1Co 5:6).

Note 2 at 1Co 5:1: The Greek word that was translated "fornication" twice in this verse, as well as twenty-two other times in the New Testament, is "PORNEIA," and it means "harlotry (including adultery and incest); figuratively, idolatry" (Strong's Concordance).

Three times (recorded in four places - Mt 15:19, Mr 7:21, 1Co 6:9, and Ga 5:19), a distinction between adultery and fornication is implied by the fact that both words are employed in a list of sins in the same verse.

However, most scholars believe that "fornication" is a broad word encompassing all sexual immorality of which adultery is just a part. Vine's Expository Dictionary defines PORNEIA as simply "illicit sexual intercourse."

Note 3 at 1Co 5:1: Today, this act of sexual immorality is called incest. The word "incest" is not used in the Bible, but the laws restricting this immorality are recorded in Le 18:6-17 (also Le 20:10-21). Le 18:8 specifically forbids sexual relations with a stepmother, which Paul was dealing with here (see also De 22:30 and 27:20).

These acts of incest were called an abomination in Le 18:26-27 and 29-30 and were all punishable by death (Le 20:10-21). Incest was placed in the same category as sacrificing children to demon gods (Le 18:21), homosexuality (Le 18:22), and bestiality (Le 18:23).