The Mystical East
Many church buildings are built in a certain position so that during Mass, the people (and the presider, if not facing the people) face the wall behind the altar ad orientem – in the direction of the dawn.
Is this custom important enough for me to spend time reading about?
We might be tempted to shrug off this hokey-cokey posturing and argue that Christ probably couldn't care less which way we face during worship, but cares very much that we DO worship. However, we must also remember that there is a reason for messages in the Bible, which we must accept and submit to, even if their underlying wisdom is not clear to us.
The oriental orientation is, of course, symbolic only. There is nowhere on earth where God isn't; and similarly there is nowhere on earth where the devil isn't lurking. There is nothing wrong with symbolism; indeed, facing east (or other postures, such as kneeling to pray) can help us in our worship, which might otherwise be limited by our pathetic inadequacy in finding the right words to say.
Steeped in Pagan worship of Sun?
Here we go again…
Take a look at the origin of the Auseklis Cross, the Latin Cross, and most other crosses. Shouldn't pagan practices be avoided by Christians? Well, yes, if you also want to avoid other things that pagans get up to; such as wearing vestments, chanting, praying, worshipping, eating, breathing, etc.
Are Christians copying Muslims by facing east to worship?
No, not at all.
Muslims face Mecca, which may be westwards of where they are. They face Mecca because that is specified in the Holy Quran as the focal point that all Muslims should turn, maintaining unity and uniformity among worshipers.
Christians face east, not only in opposition to the Jewish custom of facing west in prayer but principally because east is specified in the Holy Bible as the direction from which Christ will return, and hence the facing is an expression of eschatological hope and in anticipation of welcoming the return of Christ.
The west is associated with death. Jesus died as the sun was setting in the west, on the west of Jerusalem, and was buried in the evening (Matt. 27:57), but ascended to heaven east of Jerusalem (Acts 1:9-12)