146 If each of you strives to accomplish all this that We have recommended, there will shine forth anew in the Church that which was expressed so wonderfully about Christians in the Epistle to Diognetus : "They are in the flesh, but do not live by the flesh. They dwell on earth, but they are citizens of heaven. They obey valid laws and even go beyond the demands of law in the conduct of - their lives... They are not understood, and yet they are condemned; they are put to death, and yet their life is quickened. They are poor, and yet they make many wealthy. They lack all things, and yet they have all in abundance. They are dishonored, and yet in the midst of dishonor they find honor. Their good name is railed at, and yet is presented as evidence of their justice. They receive rebukes and give blessings in return. They suffer abuse and offer praise. When they conduct themselves like honest men, they are punished like criminals. While they are being punished, they rejoice as though they are being rewarded... To express the matter simply: what the soul is to the body, Christians are to the world." (74)
Source: Ad Petri Cathedram (Vatican.va)