Catechism of the Catholic Church

An ecclesial grace. The sick who receive this sacrament, "by freely uniting themselves to the passion and death of Christ," "contribute to the good of the People of God." By celebrating this sacrament the Church, in the communion of saints, intercedes for the benefit of the sick person, and he, for his part, though the grace of this sacrament, contributes to the sanctification of the Church and to the good of all men for whom the Church suffers and offers herself through Christ to God the Father. (953)