The Marks of the Church

In the Creed we profess the Church to be one holy catholic and apostolic.
These four characteristics, inseparably linked with each other, indicate essential features of the Church and her mission.
The Church does not possess them of herself; it is Christ who, through the Holy Spirit, makes His Church one, holy, catholic, and apostolic, and it is He who calls her to realize each of these qualities.

The Church Is One

John 17:11
Holy Father, keep them in your name that you have given me, so that they may be one just as we are.
John 17:21
... so that they may all be one, as you, Father, are in me and I in you, that they also may be in us, that the world may believe that you sent me.
Eph 4:4 - 5
There is one body and one Spirit just as you were called to the one hope that belongs to your call, one Lord, one faith, one baptism, one God and Father of us all.
1 Cor 10:17
Because there is one bread, we who are many are one body, for we all partake of the one bread.
John 10:16
(Jesus said) "there shall be one flock, one shepherd."

The Church is Holy

The Church of the apostles was holy. When we say that the Church is holy, we mean among other things that she had the all-holy God as her author.

Eph 5:25 - 27
Christ loved the church and gave himself up for her, that he might sanctify her, having cleansed her by the washing of water with the word, that he might present the church to himself in splendor, without spot or wrinkle or any such thing, that she might be holy and without blemish.
1 Tim 1:15
Christ Jesus came into the world to save sinners.

The Church is Catholic

The third great historic mark, or note, of the one true Church is that this Church is Catholic. Catholic means "universal." It refers as much to the fullness of the faith she possesses as to the undeniable extension in both time and space that has characterized her virtually from the beginning.
Mark 16:15
He said to them, "Go into the whole world and proclaim the gospel to every creature."
Col 1:5 - 6
The word of the truth ... in the whole world ... is bearing fruit and growing.

The Church is Apostolic

Finally, the Church that issued from the commission of Christ to the apostles was apostolic. Christ founded the Church upon the apostles.
John 6:70
"Did I not choose you, the twelve?" (Jesus) asked them.