Saint Paul bade the Romans not to repay evil for evil (cf. Rom 12:17), not to seek revenge (cf. Rom 12:19), and not to be overcome by evil, but instead to “overcome evil with good” (cf. Rom 12:21). This attitude is not a sign of weakness but of true strength, because God himself “is slow to anger but great in power” (Nah 1:3). The word of God exhorts us to “put away all bitterness and wrath and wrangling and slander, together with all malice” (Eph 4:31).
Gaudete et Exsultate 113