The day of the Church
36. The Sunday assembly is the privileged place of unity: it is the setting for the celebration of thesacramentum unitatis which profoundly marks the Church as a people gathered "by" and "in" the unity of the Father, of the Son and of the Holy Spirit.(49) For Christian families, the Sunday assembly is one of the most outstanding expressions of their identity and their "ministry" as "domestic churches",(50) when parents share with their children at the one Table of the word and of the Bread of Life. We do well to recall in this regard that it is first of all the parents who must teach their children to participate in Sunday Mass; they are assisted in this by catechists, who are to see to it that initiation into the Mass is made a part of the formation imparted to the children entrusted to their care, explaining the important reasons behind the obligatory nature of the precept. When circumstances suggest it, the celebration of Masses for Children, in keeping with the provisions of the liturgical norms,(51) can also help in this regard.