God incarnate

Some brilliant comments all the way from the fourth century, courtesy of Hilary of Poitiers in Book Three of De Trinitate:

A virgin bears; her child is of God.
An infant wails; angels are heard in praise.
There are coarse swaddling clothes; God is being worshipped.

The glory of his majesty is not forfeited when he assumes the lowliness of flesh.

He who upholds the universe, within whom and through whom are all things, was brought forth by common childbirth;

He at whose voice Archangels and Angels tremble, and heaven and earth and all the elements of this world are melted, was heard in childish wailing.

The Invisible and Incomprehensible, whom sight and feeling and touch cannot gauge, was wrapped in a cradle...He by whom man was made had nothing to gain by becoming man; it was to our gain that God was incarnate and dwelt among us.

...the proper service of faith is to grasp and confess the truth that it is incompetent to comprehend its Object. 

On understanding the eternal relationship between the Father and Son he says:

If anyone lays upon his personal incapacity his failure to solve the mystery, in spite of the certainty that Father and Son stand to each other in those relations, he will be still more pained at the ignorance to which I confess. 

I, too, am in the dark, yet I ask no questions.  I look for comfort in the fact that Archangels share my ignorance, that Angels have not heard the explanation, and worlds do not contain it, that no prophet has espied it and no Apostle sought for it, that the Son himself has not revealed it.

The always present Son

If Christ's sonship is not eternal then the Father's identity as Father is rendered temporal too:

"But he is Father of the always present Son, on account of whom he is called Father, and with the Son always present with him, the Father is always perfect, unfailing in goodness, who begot the only-begotten Son not temporally or in any interval or from nothing."

Alexander of Alexandria (in a letter to Alexander of Byzantium concerning the errors of Arius)

When the riddles are not resolved

Powerful and humbling words from Herman Bavinck that I am grateful to have re-read:

In the case of the Christian, belief in God's providence is not a tenet of natural theology to which saving faith is later mechanically added.  Instead, it is saving faith that for the first time prompts us to believe wholeheartedly in God's providence in the world, to see its significance, and to experience its consoling power...the Christian has witnessed God's special providence at work in the cross of Christ and experienced it in the forgiving and regenerating grace of God, which has come to one's own heart.

And from the vantage point of this new and certain experience in one's own life, the Christian believer now surveys the whole of existence and the entire world and discovers in all things, not chance or fate, but the leading of God's fatherly hand.

Special revelation is distinct from general revelation, and a saving faith in the person of Christ is different from a general belief in God's government in the world.  It is above all by faith in Christ that believers are enabled -- in spite of the riddles that perplex them -- to cling to the conviction that the God who rules the world is the same loving and compassionate Father who in Christ forgave them all their sins, accepted them as his children, and will bequeath to them eternal blessedness.

In that case faith in God's providence is no illusion, but secure and certain; it rests on the revelation of God in Christ and carries within it the conviction that nature is subordinate and serviceable to grace, and the world [is likewise subject] to the kingdom of God.  

Thus, through all its tears and suffering, it looks forward with joy to the future.  Although the riddles are not resolved, faith in God's fatherly hand always again arises from the depths and even enables us to boast in afflictions.

Reformed Dogmatics Vol. 2: God and Creation, p. 594-5