From Pope St. John Paul II’s Apostolic Exhortation Familiaris Consortio (1981):
The social role that belongs to every family pertains by a new and original right to the Christian family, which is based on the sacrament of marriage. By taking up the human reality of the love between husband and wife in all its implications, the sacrament gives to Christian couples and parents a power and a commitment to live their vocation as lay people and therefore to “seek the kingdom of God by engaging in temporal affairs and by ordering them according to the plan of God.”113
The social and political role is included in the kingly mission of service in which Christian couples share by virtue of the sacrament of marriage, and they receive both a command which they cannot ignore and a grace which sustains and stimulates them.
The Christian family is thus called upon to offer everyone a witness of generous and disinterested dedication to social matters, through a “preferential option” for the poor and disadvantaged. Therefore, advancing in its following of the Lord by special love for all the poor, it must have special concern for the hungry, the poor, the old, the sick, drug victims and those who have no family.
113 Second Vatican Council Lumen gentium, 31.
— Familiaris Consortio 47