1 Corinthians 4:13

being defamed, we entreat: we are made as the filth of the world, the offscouring of all things, even until now.

'being defamed, we entreat' -Paul applied his own preaching. (Romans 12:17) 'They answer the calumnies (slander) by entreating men to repent and to turn to Christ.' (Erdman p. 59) (Matthew 5:39; Luke 6:27)

'Finally, he concludes with the most unflattering of metaphors, indicating the world's reaction to this way of living. We who follow Christ in these ways, Paul says, do not receive the accolades of the worldly wise. To the contrary..' (Fee p. 180)

'the filth of the world, the offscouring of all things' -'To this moment we are considered the scum of the earth, the scrapings of everyone's feet.' (Ber)

'The two words, which are nearly synonymous, refer to the "off-scouring" that is removed in the process of cleansing, either sweepings from the floor, or dirt removed from the body. Both words, therefore, came to be used...for anything that is contemptible.' (Fee p. 180)

'In contrast to the Corinthians, who are "filled, rich, ruling, wise, powerful, honored", he and his fellow apostles look far more like their Lord, who fits well the picture of Isaiah 2:2 b-3' (Fee p. 181)