2. That there is only one.
According to the New Testament, there is only one church:
“…upon this rock I will build MY CHURCH…” (Matt. 16:18).
“…we have many members in ONE BODY…in Christ…” (Rom. 12:4,5).
“…we who are many are ONE BODY…” (1 Cor. 10:17).
“…this body is ONE… …baptized into ONE BODY…” (1 Cor. 12:12,13).
“…reconcile us both to God in ONE BODY through the cross…” (Eph. 2:16).
“…There is ONE BODY and one Spirit…” (Eph. 4:4).
“…you were called in ONE BODY…” (Col. 3:15).
This is not to say that all the hundreds upon hundreds of distinct, diverse, differing groups—all of whom claim to all believe in the same God, follow the same Lord, and obey the same Book—all collectively make up the “one church” of which the apostle Paul spoke so often and emphatically (cf. Rom. 12; 1 Cor. 12; Eph. 2; et al.). On the contrary, as has been seen, only those who have been “baptized into Christ” are in Christ, and are thus “added to” His body (Gal. 3:27; Acts 2:41,47), and only those who “continue steadfastly in the apostles’s teaching… [etc.]” (Acts 2:44) continue in Christ (cf. Gal. 5:1ff; 2 John 6; et al.).
In other words, there is only one church—one body—that is in Christ (cf. Gal. 1:22; 1 Thess. 2:14); ALL others are out of Christ, because they are not abiding in Christ, and are thus neither sanctified nor recognized by Him (cf. Matt. 7:21-23; Col. 2:23; Gal. 3:26-29; 5:1ff; et al.).
3. That it will never end—and thus is identifiable.
When Daniel prophesied about the coming kingdom of God in Dan. 2:36-44, he said two fundamental things about it:
It would be established in the days of the Roman Empire (v. 44a);
It would be destroyed never (v. 44b).
There will never be another kingdom of God. The church that Jesus built and purchased with His blood is it—and it is here. Are you a part of it? You can be; the church wants you to be; God wants you to be; and He has told you how to do so (cf. John 3:3-5; Mark 16:15,16; Acts 2:38; 22:16; Rom. 6:3,4; 10:10,17; Gal. 3:26,27; 1 Pet. 3:21).