The doors of Hell are locked on the inside

I willingly believe that the damned are, in one sense, successful, rebels to the end; that the doors of Hell are locked on the inside. I do not mean that the ghosts may not wish to come out of Hell, in the vague fashion wherein an envious man wishes to be “happy”; but they certainly do not will even the first preliminary stages of that self abandonment through which alone the soul can reach any good. They enjoy forever the horrible freedom they have demanded, and are therefore self-enslaved; just as the blessed, forever submitting to obedience, become through all eternity more and more free.

C.S. Lewis
The Problem of Pain

Humanism is irrational

The humanist’s faith is based on his belief that nonrational causes cause rational beings (humans with minds) who are themselves composed entirely of the nonrational, and yet are somehow able to step outside of that nonrationality and reason to the conclusion that everything is material and therefore nonrational. Yet, if the nonrational material universe is “the whole show,” the humanist could never actually know if he is truly rational or only a nonrational material product with the illusion of rationality.

What is more reasonable to believe, that the nonrational produces the rational; or that a rational being (God) created other rational beings (humans) and a world founded on rational principles that can therefore be understood by these rational beings? The humanist must borrow from the theistic, Christian worldview, which can account for rationality. It is ironic that humanists often accuse Christians of possessing blind faith that the nonrational can produce the rational. Christianity gives birth to science, while humanism only gives birth to blindness.

Bob and Gretchen Passantino
Religion, Truth, and Value without God: Contemporary Atheism Speaks Out in Humanist Manifesto 2000 (Part Two)

The Holy Spirit enables man to fulfill his calling as a creature of God

The Christian Church lives by the Holy Spirit. The Spirit alone is the guarantee of God’s Kingdom on earth. He is the sole guarantee that God’s life and truth and love are with men. Only by the Holy Spirit can man and the world fulfill that for which they were created by God. All of God’s actions toward man and the world—in creation, salvation and final glorification—are from the Father through the Son (Word) in the Holy Spirit; and all of man’s capabilities of response to God are in the same Spirit, through the same Son to the same Father.

Thomas Hopko
From the Series: The Orthodox Church
Volume I – Doctrine and Scripture: The Symbol of Faith

Virtue is a gift from God — man is not capable.

Consider how [Jesus Christ] teaches us to be humble, by making us see that our virtue does not depend on our work alone but on grace from on high. He commands each of the faithful who prays to do so universally, for the whole world. For he did not say “thy will be done in me or in us”, but “on earth”, the whole earth, so that error may be banished from it, truth take root in it, all vice be destroyed on it, virtue flourish on it, and earth no longer differ from heaven.

St. John Chrysostom
On the Lord’s Prayer

Liberty only leads man further into sin

It is a remarkable phenomenon in nature that, if you put a plant into a large, wide pot or tub, it grows very much at the roots; they thicken, they give out many ramifications, but the tree itself does not grow much in height, and only yields few and small leaves and flowers. But if it is planted in a small pot, then the roots are small, but the plant itself grows rapidly in height and yields beautiful leaves and flowers (if it is the nature of the plant to produce flowers). Is it not the same with man? When he lives in full liberty, in abundance and prosperity, then he grows in body and does not grow in spirit, does not bring forth fruits — good works; whilst when he lives in straightness, in poverty, sickness, misfortune, and afflictions, in a word, when his animal nature is crushed, then he grows spiritually, bears flowers of virtue, ripens and brings forth rich fruits. This is why the path of those who love God is a narrow one.

St. John of Krondstat
On Good Works