the geneva catechism 4
95. You mean then that up to this point we have spoken of the cause and foundation of salvation, how God has received us in love through the mediation of Jesus, and has confirmed this grace in us through His Holy Spirit. But now the effect and fulfillment of all this is explained in order to give us greater certainty. It is so.
96. In what sense do you call the Church holy? All whom God has chosen He justifies, and reforms to holiness and innocence, that His glory may be reflected in them (Rom. 8:30). And so Jesus Christ sanctified the Church which He redeemed, that it might be glorious and without blemish (Eph. 5:25-27).
97. What is meant by the word Catholic or Universal? It is meant to signify, that there is only one Head of the faithful, so they must all be united in one body, so that there are not several churches but one only, which is extended throughout the whole world (Eph. 4:15; 1 Cor. 12:12 and 27).
98. And what is the meaning of what follows concerning the communion of saints? That is added to express more clearly the unity which exists among the members of the Church. Moreover by this we are given to understand, that all the benefits that the Lord gives to the Church, are for the good and salvation of every Church, because they all have communion together.
99. But is this holiness which you attribute to the Church already perfect? Not as long as she battles in this world, for elements of imperfection always remain and will never be entirely removed, until she is united completely to Jesus Christ her Head, by whom she is sanctified.
100. Can this Church be known in any other way than by believing in her? There is indeed the visible Church of God, for the recognition of which He has certain signs, but here we speak properly of the fellowship of those whom He has elected to salvation which cannot be seen plainly by the eye.
101. What comes next? I believe in "the forgiveness of sins".