The adoption of the eastward direction for worship by Christians also represented a reaction against the Jewish practice of turning towards Jerusalem to pray. The East symbolized the heavenly Jerusalem in contrast with the earthly Jerusalem of the Jews. The Christians of antiquity found a rich and seemingly inexhaustible symbolism in the eastward direction. Christians worshipped not the sun king but the King of the sun, because the sun itself was created by Christ (non est Dominus Sol factus, sed per quem Sol factus est). Our Lord had faced the West while offering the Sacrifice of His Life upon the Cross, and so by facing eastwards during the Mass we are actually facing Him, because the Sacrifice of the Cross is made present during the Mass. The unconquered sun of paganism (sol invictus) had become a symbol for the unconquered Son of God, the victor over death and Satan, the sun of salvation (sol salutis). Christ had risen from His tomb as surely as the sun rose in the East each day, and every sunrise was a cause of hope to the first Christians whose lives were permeated by the joy of the Resurrection; they were truly described as "an Easter-people". St. Thomas Aquinas taught that the eastward direction symbolized both Paradise Lost and Paradise Regained. Paradise had been situated in the East, and so by worshipping in this direction we symbolize our desire to regain Paradise, the heavenly Paradise represented by the East. There are also traditions that just as the birth of the Messiah was heralded by a star in the East (stellam ejus in Oriente), His Second Coming will be like lightning coming from the same direction (sicut enim fulgur exit ab oriente ---Matt. 24:27). There is also a tradition that the Second Coming will take place during the celebration of Mass. With their eyes fixed on the East, priest and people will be prepared to receive Our Lord in an attitude of adoration.
It should now be apparent how fatuous it is to speak of the priest celebrating Mass with "his back to the people". During Mass the priest stands between people and altar, a mediator between God and man, the outermost representative of humanity, standing at the very point where Heaven and earth come together when God the Son is brought down upon the altar as our Sacrificial Victim (hostia). The priest is also like a shepherd in eastern countries. He does not need to drive his flock from behind, to watch them lest they stray. We walks before them, leading them to green pastures or the safety of their fold. They know him and he knows them. But Catholics at worship today no longer look outwards and upwards to Heaven, no longer fix their hearts and minds upon Our Lord. Contemporary Catholicism is an introspective religion, symbolized aptly by the turning round of the altar so that, turned in upon themselves, priest and people can fix their minds upon each other.