The church is connected with the general history of salvation. Belonging to Christ means to integrate his life story in the history of salvation.
This is according to the Catholic understanding associated with the life of the Church. It should reflect how that "belong to Christ" grab.
Text is conceived in three steps: (1) access from the perspective of Christian anthropology, (2) follows passage of soteriology. The third aspect reflects the essential character of the Church is fundamentally sacramental feature of its existence.
These three aspects so we can see the status of a person who has been incorporated into the Church through baptism.