No doubt to-morrow I will hide
My face from you, my King.
Let me rejoice this Sunday noon,
And kneel while gray priests sing.

It is not wisdom to forget.
But since it is my fate
Fill thou my soul with hidden wine
To make this white hour great.

My God, my God, this marvelous hour
I am your son I know.
Once in a thousand days your voice
Has laid temptation low.

Vachel Lindsay

http://www.poemhunter.com/poem/at-mass/