Augustine was for a time a Donatist, but his truth-loving spirit soon
discovered the real character of Donatus, and then he became his active
and uncompromising opponent. It was probably as a protest against the
arrogance of the Donatists, and in deference to Augustine's wish, that
the clause was inserted. In this profession it is declared that the Holy
Catholic Church is one not in virtue of outward forms, or even through
perfect agreement among its members upon all details of doctrine, but
because of the holiness of those who compose it. It refuses to
excommunicate any who hold fast the form of sound words, and who adhere
to one Lord, one faith, one baptism, one God and Father of all. It is a
brotherhood of which all who have the spirit of Christ are members.
Differences in colour, or country, or rank do not suffice to separate
those who are "the body of Christ and members in particular." The spirit
of Christian fellowship that marks the saints finds fitting expression
in the noble words of Augustine, "In things essential, unity; in things
doubtful, liberty; in all things, charity."

The primary meaning of the word "saint" is a person consecrated or set
apart. In this sense all baptized persons who are professing members of
the Church of Christ are saints. In the New Testament the whole body of
professing Christians resident in a city or district are called saints,
although some among them may have been unworthy; just as in the Old
Testament the prophets even in degenerate times termed the people of
Israel an "holy nation," that is, a nation separated from the rest of
the world and consecrated to God's service. Thus we read that Peter
visited the saints which dwelt at Lydda.[193] Paul speaks of a
collection for the poor saints at Jerusalem, and writes letters to all
the saints in Achaia,[194] to all the saints in Christ Jesus at
Philippi, and to the saints at Ephesus; and Jude speaks of the faith