Frequently, groups will tout their membership because they claim the members are their strength. Such is not the case with the Church. Our strength is not our people; for we are sinners. St. Paul writes: "For all have sinned, and come short of the glory of God." (Romans 3:23). Rather our strength is the Marks of the Church. The Marks of the Church are Holy Baptism, the Word and the Lord's Supper. Each one of these Marks has been Divinely established by God Himself. 

Through these Marks God gives His Grace. God's Grace or Gift is the free remission of all sins for Christ's Sake. St. Paul writes: "The Gospel is the power of God unto salvation." (Romans 1:16) This life-giving Gospel comes also through the waters of Holy Baptism. St. Paul writes: "That He might sanctify and cleanse it [the Church] with the washing of water by the Word." (Ephesians 5:25) This Grace is also given in the Lord's Supper. Jesus says, "This cup is the New Testament in My Blood shed for you." (Luke 22:19, 20).

These Marks of God's Grace mark the Church; for God gathers His Church through the proclamation of the free forgiveness of all sins for Christ's sake.

And here it is also seen that the Church's Strength is not her members (we are the weakest part because we are sinners) but rather God Himself in His Divinely appointed Institutions: His Word and His Sacraments.

Because the Church's Strength is Christ's righteousness for us given us in the Marks of the Church, the prophet Jeremiah rightly identifies the Church according to her Strength:

"In those days shall Judah be saved, and Jerusalem shall dwell safely: and this is the name wherewith she shall be called, the LORD is Our Righteousness." Jeremiah 33:16