In his book, How Christ Said the First Mass, Fr. James Meagher relates how deeply rooted the Mass is in the Jewish temple tradition. This makes great sense as the Apostles and all of the Jewish converts knew God was the same God, only now with the fullness of revelation as Father, Son, and Holy Spirit. They weren't about to create something out of thin air, after all many of the rituals of the temple were given them directly by God.
In the picture on the left, you can see that, right before the steps up to the temple itself, there is the priests' court. We should recall that by Christ, through our baptism, we are given a universal priesthood, a priestly people. They were all facing towards the Holy of Holies (on this diagram called the "Most Holy Place", which is covered by the veil). Inside the Holies (on this diagram called the "Holy Place"), there was the table of bread and wine as well as the candles, which were for the offering. When the high priest took the incense, he went into the Holy of Holies alone but always facing forward towards the Ark of the Covenant (when they had it) or the Altar of Incense (when the ark was hidden away from them)...this place was also referred to as the Tabernacle, before the temple.
Today, in the ad Deum arrangement, we worshipping in a continuous manner. The high priest, chosen among the priestly group (universal priest people), to offer the sacrifices from among the offerings brought by the priestly group. He alone enters the Holy of Holies, what we would call the sanctuary to offer first incense, which demonstrates the presence of God in the tabernacle. Then he makes the offering of the bread and the wine. The moment he turns to the priestly group is to lift up and show them the bread offered, that in it they might see even God's visage. The priest today turns from the altar before God to bring the Bread of Life; when he elevates the Eucharist, he says: Behold the Lamb of God!
What laid stored up in the temple worship for the Jews (like an acorn) has now sprung full fledged into the mighty oak of the Holy Mass (like the oak). The acorn did not stop being an oak; instead, it became more oak...the fullness of what the seed was supposed to become. Likewise, the oak did not exist fully fledged, but it started as the acorn.
The priestly people of God face the Lord God to do Him homage and worship. Should the sacramental priest do any less?