Augustine of Hippo
True martyrs are those whom our Lord Jesus Christ refers to when He declares: Blessed are those who are persecuted for righteousness' sake, for theirs is the kingdom of heaven (Matthew 5:10). Thus, individuals who suffer for unrighteousness or the strife caused by these unrighteous people among Christians do not qualify as true martyrs. In contrast, those who endure persecution for the sake of truth are the true martyrs. For instance, Hagar was cast out by Sarah, who began to oppress her (see Genesis 16:6); however, in this scenario, it was the righteous woman who acted as the oppressor, while the sinner was the one being persecuted. Would it be appropriate to equate the persecution of sinful Hagar by the righteous Sarah with the suffering of St. David at the hands of the sinful Saul? Certainly not, and not simply because David underwent great hardship, but because he suffered for the cause of truth.