Reward and punishment begin before the resurrection

And, moreover, thou sayest, Who is He who has redeemed from death, that we may believe in Him, since there punishments are awarded?  Ah! not thus, O malignant man, shall it be as thou thinkest.  For to him who has lived well there is advantage after death.  Thou, however, when one day thou diest, shalt be taken away in an evil place.  But they who believe in Christ shall be led into a good place, and those to whom that delight is given are caressed; but to you who are of a double mind, against you is punishment without the body.

Commodianus
Instructions of Commodianus
Chapter XXIV

Baptism is an essential part of the New Covenant

Here, then, those miscreants provoke questions. And so they say, “Baptism is not necessary for them to whom faith is sufficient; for withal, Abraham pleased God by a sacrament of no water, but of faith.” But in all cases it is the later things which have a conclusive force, and the subsequent which prevail over the antecedent. Grant that, in days gone by, there was salvation by means of bare faith, before the passion and resurrection of the Lord. But now that faith has been enlarged, and is become a faith which believes in His nativity, passion, and resurrection, there has been an amplification added to the sacrament, viz., the sealing act of baptism; the clothing, in some sense, of the faith which before was bare, and which cannot exist now without its proper law.

Tertullian
On Baptism
Chapter XIII

Man is justified by the righteousness of God which is the faith of Christ

It was once the law; now it is “the righteousness of God which is by the faith of (Jesus) Christ.” What means this distinction? Has your god been subserving the interests of the Creator’s dispensation, by affording time to Him and to His law? Is the “Now” in the hands of Him to whom belonged the “Then”? Surely, then, the law was His, whose is now the righteousness of God. It is a distinction of dispensations, not of gods.  He enjoins those who are justified by faith in Christ and not by the law to have peace with God.

…Now, as peace is only possible towards Him with whom there once was war, we shall be both justified by Him, and to Him also will belong the Christ, in whom we are justified by faith, and through whom alone God’s enemies can ever be reduced to peace.

Tertullian
The Five Books Against Marcion, Book V
Chapter XIV

Tertullian argues that no one is worthy of heaven on the basis of merit

And yet the latter opinion ought to be discussed, that God conferred divine honours in consideration of meritorious claims. Well, then, if the award was made on such grounds, if heaven was opened to men of the primitive age because of their deserts, we must reflect that after that time no one was worthy of such honour; except it be, that there is now no longer such a place for any one to attain to.

Tertullian
Ad Nationes, Book II
Chapter XIII

Works cannot save a man

My most merciful and all-merciful God, O Lord Jesus Christ! In Thy great love, Thou didst come down and become flesh in order to save all. Again, I pray Thee, save me by Grace! If Thou shouldst save me because of my deeds, it would not be a gift, but merely a duty. Truly, Thou aboundest in graciousness and art inexpressibly merciful! Thou hast said, O my Christ: “He who believes in me shall live and never see death”. If faith in Thee saves the desperate, behold: I believe! Save me, for Thou art my God and my Maker. May my faith replace my deeds, O my God, for Thou wilt find no deeds to justify me. May my faith be sufficient for all. May it answer for me; may it justify me; may it make me a partaker of Thine eternal glory; and may Satan not seize me, O Word, and boast that He has torn me from Thy hand and fold. O Christ my Savior: save me whether I want it or not! Come quickly, hurry, for I perish! Thou art my God from my mother’s womb. Grant, O Lord, that I may now love Thee as once I loved sin, and that I may labor for Thee without laziness as once I labored for Satan the deceiver. Even more, I will labor for Thee, my Lord and God Jesus Christ, all the days of my life, now and ever and unto ages of ages. Amen.

Orthodox prayer for salvation by grace

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

We are nothing without Christ. All our good is His Good.

I am morally nothing without the Lord. I have really not one true thought or good feeling, and can do no good works; without Him I cannot drive away from me any sinful thought, any passionate feeling such as malice, envy, fornication, pride, and so forth. The Lord is the accomplishment of everything good that I think, feel, and do. O, how boundlessly wide is the Lord’s grace acting in me! The Lord is everything to me, and so clearly, so constantly. Mine — is only my sinfulness; mine — are only mine infirmities.

St. John of Krondstat
On Good Works

Works cannot merit salvation

When the foolish thought of counting up any of your good works enters into your head, immediately correct your fault and rather count up your sins, your continual and innumerable offenses against the All-merciful and Righteous Master, and you will find that their number is as the sand of the sea, whilst your virtues in comparison with them are as nothing.

St. John of Kronstadt
On Good Works