It is Christ's church...

Mat 16:18 And I tell you, you are Peter, and on this rock I will build my church, and the gates of hades shall not prevail against it.

We also know that the church is His body...

Eph 5:23 For the husband is the head of the wife even as Christ is the head of the church, his body, and is himself its Savior.

Col 1:24 Now I rejoice in my sufferings for your sake, and in my flesh I am filling up what is lacking in Christ's afflictions for the sake of his body, that is, the church,

And as you stated... there is only one church (His body)...

Eph 4:4 There is one body and one Spirit--just as you were called to the one hope that belongs to your call--

__________________
In Christ,
brother Sonnie

Jeremiah 6:16 Thus says the LORD: "Stand in the ways and see, And ask for the old paths, where the good way is, And walk in it; Then you will find rest for your souls. But they said, 'We will not walk in it.'