Augustine of Hippo — as excerpted in the Catena Aurea on Matthew 5:38-42

“(Enchir. 78.) The Lord here forbids his disciples to have lawsuits with others for worldly property. Yet as the Apostle allows such kind of causes to be decided between brethren, and before arbiters who are brethren, but utterly disallows them without the Church, it is manifest what is conceded to infirmity as pardonable.”