Solomon’s Temple was much larger than the Tabernacle of Moses, in part because it was also intended to be a house of prayer for all nations, the Gentiles. As a matter of fact, Gentiles helped build the Temple.
When Solomon dedicates the Temple in 2 Chronicles 6, orientation of prayer is explicit.
6 Then Solomon said,
“The Lord has said that he would dwell in thick darkness.
2 I have built thee an exalted house,
a place for thee to dwell in for ever.”
3 Then the king faced about, and blessed all the assembly of Israel, while all the assembly of Israel stood.
See that? To begin, he turns to address the people.
12 Then Solomon stood before the altar of the Lord in the presence of all the assembly of Israel, and spread forth his hands. 13 Solomon had made a bronze platform five cubits long, five cubits wide, and three cubits high, and had set it in the court; and he stood upon it. Then he knelt upon his knees in the presence of all the assembly of Israel, and spread forth his hands toward heaven;
In Solomon’s prayer of dedication of the Temple in 2 Chronicles 6, he said:
32 “Likewise when a foreigner, who is not of thy people Israel, comes from a far country for the sake of thy great name, and thy mighty hand, and thy outstretched arm, when he comes and prays toward this house, 33 hear thou from heaven thy dwelling place, and do according to all for which the foreigner calls to thee; in order that all the peoples of the earth may know thy name and fear thee, as do thy people Israel, and that they may know that this house which I have built is called by thy name.
“TOWARD THIS HOUSE”… that’s because the Presence of God was in the Temple upon the Ark in the Holy of Holies.
34 “If thy people go out to battle against their enemies, by whatever way thou shalt send them, and they pray to thee toward this city which thou hast chosen and the house which I have built for thy name, 35 then hear thou from heaven their prayer and their supplication, and maintain their cause.
Toward Jerusalem, because that’s where the Temple is. And if people were taken into captivity,…
36 “If they sin against thee—for there is no man who does not sin—and thou art angry with them, and dost give them to an enemy, so that they are carried away captive to a land far or near; 37 yet if they lay it to heart in the land to which they have been carried captive, and repent, and make supplication to thee in the land of their captivity, saying, ‘We have sinned, and have acted perversely and wickedly’; 38 if they repent with all their mind and with all their heart in the land of their captivity, to which they were carried captive, and pray toward their land, which thou gavest to their fathers, the city which thou hast chosen, and the house which I have built for thy name,
Then, the Presence of God is called by Solomon to descend on the Temple.
41 “And now arise, O Lord God, and go to thy resting place,
thou and the ark of thy might.
Let thy priests, O Lord God, be clothed with salvation,
and let thy saints rejoice in thy goodness.
42 O Lord God, do not turn away the face of thy anointed one!
Remember thy steadfast love for David thy servant.”
Those who try to forbid ad orientem worship are GETTING IT WRONG.
Prayers addressed by the priest to God should be pronounced so that all, priest and people, are FACING THE SAME WAY. When the priest addresses the people, he turns around to face them.
Much of Holy Mass aligns with the structure of the Temple and the worship that took place there. They did what they did for reasons that looked both backward to God’s own rubrics for worship and forward to the fulfillment of what they could only hope about… and which we have.