What It Means to Be in Christ
By :
The sacraments, much like the issue of personal identity, are subject to debate and confusion. Numerous catechisms ask, “What is a sacrament?”—a question that leads some Christians
to enter into intense theological and pastoral disputes and causes others to recoil in fear of appearing ignorant or of potentially offending those who hold divergent opinions.
Still others apply their own personal understanding to these ancient rites while disregarding how Christians of past generations have understood and practiced them. If we wish to see clearly the connection between the sacraments and Christian identity, we must get clear on what the sacraments are. Before we are able to explore in detail what the sacraments teach us about being in-Christ persons, we must first understand how they are able to teach us—and indeed form us. The sacraments are sources of revelation—alongside though never instead of or above Scripture—means through which God communicates his love and goodness to his children. Let’s now consider additional though related features of the sacraments, features that help us see more clearly how baptism and Communion are able to declare what it means to be in Christ and to shape us into persons who become like him.
Reference - https://www.crossway.org/articles/the-sacraments-give-us-a-collective-identity/