Why does Matthew use the word porneia (“except for immorality”) instead of the word moicheia which means adultery? Almost all commentators seem to make the simple assumption again that porneia means adultery in this context. The question nags at me why Matthew would not use the word for adultery, if that is in fact what he meant.
Then I noticed something very interesting. The only other place besides Matthew 5:32 and 19:9 where Matthew uses the word porneiais in 15:19 where it is used alongside of moicheia. Therefore, the primary contextual evidence for Matthew’s usage is that he conceives of porneia as something different than adultery. Could this mean, then, that Matthew conceives of porneia in its normal sense of fornication or incest (l Corinthians 5:1) rather than adultery?