John Chrysostom

"Our fathers had the tabernacle of witness in the wilderness, as he had appointed, speaking unto Moses, that he should make it according to the fashion he had seen." "But a Tabernacle," say you, "there was (the Tabernacle) 'of Witness.'" (Yes,) this is why it was: that they should have God for Witness: this was all. "According to the fashion," it says, "that was shown thee on the mount:" so that on the mount was the Original. And this Tabernacle, moreover, "in the wilderness," was carried about, and not locally fixed. …

Homily on Acts 17 ↗

Theophylact of Ohrid

"The tabernacle of witness was with our fathers in the wilderness." They had it in order to have God as a witness. He calls it the tabernacle of testimonies, that is, of miracles and commandments. "As He who spoke to Moses commanded." The establishment of the tabernacle took place on the mountain, and in the wilderness it was portable, not fixed in one place. Even if it was an Angel who spoke with Moses on the mountain, he nevertheless spoke with him on behalf of God. And there is much of this kind in Divine Scripture. …

Commentary on Acts ↗

Oecumenius

The tent of testimony, that is, of the commands of God, which was the tent of Moses shown by God on Mount Sinai. It was said to have been established by God so that they would have God as witness, because its explanation was on the mountain, and he himself had described it to Moses.

Commentary on Acts ↗

Bede

The tabernacle of testimony was with our fathers in the desert. Because they said he was acting against the holy place, here he shows that the Lord does not greatly esteem decorated stone but desires the splendor of heavenly souls. Where he wants it to be understood that just as the tabernacle was in the wilderness before the construction of the temple, so they should understand the temple itself to be destroyed when a better state succeeds. …

Commentary on Acts ↗