22 As the years went by and the Church spread further afield, the exercise of charity became established as one of her essential activities, along with the administration of the sacraments and the proclamation of the word: love for widows and orphans, prisoners, and the sick and needy of every kind, is as essential to her as the ministry of the sacraments and preaching of the Gospel. The Church cannot neglect the service of charity any more than she can neglect the Sacraments and the Word. A few references will suffice to demonstrate this. Justin Martyr († c . 155) in speaking of the Christians' celebration of Sunday, also mentions their charitable activity, linked with the Eucharist as such. Those who are able make offerings in accordance with their means, each as he or she wishes; the Bishop in turn makes use of these to support orphans, widows, the sick and those who for other reasons find themselves in need, such as prisoners and foreigners. The great Christian writer Tertullian († after 220) relates how the pagans were struck by the Christians' concern for the needy of every sort. And when Ignatius of Antioch († c . 117) described the Church of Rome as “presiding in charity ( agape )”, we may assume that with this definition he also intended in some sense to express her concrete charitable activity.
Source: Deus Caritas Est (Vatican.va)