John Chrysostom, on preparing for Sunday worship (or Saturday, for you 7th Day brothers):

[W]e are to-day to set foot within the holy vestibule, wherefore I have also put you in mind of the charge.

Since, if the Jews, when they were to approach “a mountain that burned, and fire, and blackness, and darkness, and tempest;” or rather when they were not so much as to approach, but both to see and to hear these things from afar;—were commanded for three days before to abstain from their wives, and to wash their garments, and were in trembling and fear, both themselves and Moses with them; much more we, when we are to hearken to such words, and are not to stand far from a smoking mountain, but to enter into Heaven itself, ought to show forth a greater self-denial; not washing our garments, but wiping clean the robe of our soul, and ridding ourselves of all mixture with worldly things. For it is not blackness that ye shall see, nor smoke, nor tempest, but the King Himself sitting on the throne of that unspeakable glory, and angels, and archangels standing by Him, and the tribes of the saints, with those interminable myriads.

For such is the city of God, having “the Church of the first-born, the spirits of the just, the general assembly of the angels, the blood of sprinkling,” [Heb. 12.22, 23, 44] whereby all are knit into one, and Heaven hath received the things of earth, and earth the things of Heaven, and that peace hath come which was of old longed for both by angels and by saints.

Herein standeth the trophy of the cross, glorious, and conspicuous, the spoils won by Christ, the first-fruits of our nature, the treasures of our King; all these, I say, we shall out of the Gospels know perfectly. If thou follow in becoming quietness, we shall be able to lead thee about everywhere, and to show where death is set forth crucified, and where sin is hanged up, and where are the many and wondrous offerings from this war, from this battle…. From "Homily on Matthew 1.1"