VISIBLE OR INVISIBLE. The Church is invisible, because we cannot read men's hearts nor tell who are real believers. But if we regard the Church as an external organization which includes all who profess to believe, it is visible. In this outward visible Church there are many persons who are not real believers. But Christ knows His own. [II Tim 2:19+, John 10:14+] The angels on the day of judgment will separate the hypocrites from the true Christians. [Matt. 13:41, 42] THE MARKS OF THE CHURCH. The Church is found wherever the Gospel is rightly taught and the Sacraments are rightly administered. For wherever God's Word is preached, some persons believe it, [Isa. 55:10, 11] and where believers are, there is the Church. THE CHURCH IS ONE. It consists of the true believers out of all the different churches, denominations, and sects. There is one Flock, with one Shepherd. [John 10:16] The Church is the Body of which Christ is the Head. [Col. 1:18, Eph 1:22, 23] ITS NAMES. The Church is called _Holy_, because the Holy Spirit works in it and through it, and because its members, though not perfect, lead holy lives. It is called _Christian_, because it consists of those who believe in Christ. It is called _Catholic_ or Universal, because it is meant to include all men everywhere. Catholic does not mean _Roman_ Catholic. MILITANT AND TRIUMPHANT. The Church, consisting of true believers, is one and the same Church on earth and in heaven. On earth it is the Church Militant, because its members are still fighting the good fight of faith. [I Tim. 6:12+] In heaven it is the Church Triumphant, because its members have won the victory of faith. [Rev. 7:9-14, Rev. 2:18, Rev. 3:21] The only way into the Church Triumphant is through the Church Militant. THE CHURCH'S WORK. The Church is the agency or instrument which the Holy Spirit uses for the evangelization of the world. [Matt. 28:19, Mark 16:15] It is the institution through which He does His work of applying redemption to the souls of men. The Church, therefore, has a work to do: namely, to make disciples of all men. THE MEANS through which the Church, as an agency of the Holy Spirit, is to do its work are the Word of God and the Sacraments. They are sufficient for the purpose for which they are intended, because the Holy Spirit works through them and endows them with supernatural power. [Rom. 1:16, Heb. 4:12]