Albert Barnes on Revelation 21:3

And I heard a great voice out of heaven. As if uttered by God himself, or the voice of angels.

Behold, the tabernacle of God is with men. The tabernacle, as that word is commonly used in the Scriptures, referring to the sacred tent erected in the wilderness, was regarded as the peculiar dwelling-place of God among his people--as the temple was afterwards, which was also called a tabernacle. Heb 9:2. The meaning here is, that God would now dwell with the redeemed, as if in a tabernacle, or in a house specially prepared for his residence among them. It is not said that this would be on the earth, although that may be; for it is possible that the earth, as well as other worlds, may yet become the abode of the redeemed. 2Pet 3:13.

And he will dwell with them. As in a tent, or tabernacle--σκηνωσει. This a common idea in the Scriptures.

And they shall be his people. He will acknowledge them in this public way as his own, and will dwell with them as such.

And God himself shall be with them. Shall be permanently with them; shall never leave them.

And be their God. Shall manifest himself as such, in such a manner that there shall be no doubt.

(c) "tabernacle of God" 2Cor 6:16 (d) "his people" Zech 8:8