Note 4 at 1Co 4:13: Paul's use of the phrases "filth of the world" and "offscouring of all things" alluded to certain heathen customs of his day. These were the phrases used to refer to certain human sacrifices.

The Greeks would choose the most worthless person available and maintain that person for one year at public expense--in effect, fattening him or her for the kill. Then, with great circumstance, they would offer that person as a sacrifice to the gods and say, "Be thou our propitiation."

Paul was saying that this was the way the Corinthians had viewed him. They had forgotten that Paul was the one the Lord used to introduce them to Christ (1Co 4:15).