The Church as "the house" and as "the body of Christ" began on the day of Pentecost. Acts, chapter 2, records the way in which it took place; and 1 Cor. 12:13, tells us that all were then baptized by ONE SPIRIT into ONE BODY.
This was a "saved remnant" from among the Jews, to which was afterward added the Gentiles in Acts, chapter 10. This was fulfilling the word in John 10:16, which is correctly rendered "one flock," and also the word in chapter 11:52, which speaks of the gathering together "in one" the children of God that were scattered abroad.
Paul received by revelation the wondrous mystery of what had taken place. Christ and we i;re one! (Eph. 3:1-7.)
We may get bad material when the Church is viewed as the house, for man may add that which is not real; but all is good material when it is the body, for it is the Holy Spirit that unites to Christ in glory.
The "one loaf" on the table in the breaking of bread is the precious symbol of this unity formed by the Spirit. (1 Cor. 10:17.) Such an assembly is an "assembly of the saints." (1 Cor. 14:33.)
LORD JESUS! are we one with Thee?
O height! O depth of love!
And crucified and dead with Thee,
Now one in heaven above.
Such was Thy grace, that for our sake
Thou didst from heaven come down;
With us of flesh and blood partake,
And make our guilt Thine own.
Our sins, our guilt, in love divine,
Confessed and borne by Thee;
The gall, the curse, the wrath were Thine,
To set Thy ransomed free.
Ascended now, in glory bright,
Life-giving Head Thou art;
Nor life, nor death, nor depth, nor height,
Thy saints and Thee can part.
And soon shall come that glorious day,
When, seated on Thy throne,
Thou shalt to wondering worlds display
That we with Thee are one.