Spirituality: St. Gregory Nazianzen, Oration 38 on the Nativity of the Lord:

Christ is born, glorify him!

Christ from heaven, go out to meet him!

Christ on earth, be exalted!

Sing to the Lord all the whole earth, and that I may join both in one word, let the heavens rejoice, and let the earth be glad, for him who is of heaven and then of earth.

Christ is in the flesh, rejoice with trembling and with joy;

with trembling because of your sins, with joy because of your hope.

Christ of a Virgin; matrons live as virgins, that you may be mothers of Christ.

Who does not worship Him who is from the beginning?

Who does not glorify Him who is the last?

Once again the darkness is past;

once again light is made;

once again Egypt is punished with darkness;

once again Israel is enlightened by a pillar.

The people that sat in the darkness of ignorance, let it see the great light of full knowledge.

Old things have passed away: behold all things have become new.

The letter gives way: the Spirit comes to the fore.

The shadows flee away, the truth comes in upon them.

Melchizedech is perfected.

He that was without mother comes into existence without a father

(without mother in His earlier state, without father in His later).

The laws of nature are overturned: the world above must be filled.

Christ commands it: let us not set ourselves against Him.

Clap your hands all you people, for to us a child is born, and to us a son is given, whose government is upon his shoulder (for with the Cross it is raised up), and his name is ‘the Angel of the Father’s Great Counsel’.

Let John cry, ‘Prepare the way of the Lord!’ I too will cry the power of this day!

He who is fleshless becomes flesh, the Son of God becomes the son of man,

Jesus Christ the Same yesterday, and to-day, and for ever! …

Let this Festival be common to the powers in heaven and to the powers upon earth. For I am persuaded that the heavenly hosts join in our exultation and keep high Festival with us to-day, because they love humankind, and they love God … Look at and be looked at by the Great God, who in Trinity is worshipped and glorified, and Whom we declare to be now set forth as clearly before you as the chains of our flesh allow, in Jesus Christ our Lord, to Whom be the glory for ever. Amen!