Christ’s Risen Life is Given to Us in the Church through Baptism

The fruit of Baptism, its true fulfillment, is a new life; not simply a better, more moral or even more pious life, but a life ontologically different from the “old” one. And this difference, the very content of this “newness,” is that it is life with Christ: “…if we be dead with Christ, we believe that we shall also live with Him” (Rom 6:8). It is His Risen Life “unto God” that is given to us and becomes our life and our resurrection. But his Life in us, our life in Him is precisely the Church, for she has no other being, no other purpose and no other life but to be Christ in us and we in Christ.”

Alexander Schmemann
Of Water and Spirit
pg. 120

Man’s free will to sin gives Satan power over him

From which it follows, that in the case of every creature it is a result of his own works and movements, that those powers which appear either to hold sway over others or to exercise power or dominion, have been preferred to and placed over those whom they are said to govern or exercise power over, and not in consequence of a peculiar privilege inherent in their constitutions, but on account of merit.

…Now it is certain that by the dragon is understood the devil himself.  If then they are called opposing powers, and are said to have been once without stain, while spotless purity exists in the essential being of none save the Father, Son, and Holy Spirit, but is an accidental quality in every created thing; and since that which is accidental may also fall away, and since those opposite powers once were spotless, and were once among those which still remain unstained, it is evident from all this that no one is pure either by essence or nature, and that no one was by nature polluted.  And the consequence of this is, that it lies within ourselves and in our own actions to possess either happiness or holiness; or by sloth and negligence to fall from happiness into wickedness and ruin, to such a degree that, through too great proficiency, so to speak, in wickedness (if a man be guilty of so great neglect), he may descend even to that state in which he will be changed into what is called an “opposing power.”

Origen
On First Principles, Book I
Chapter V

Every sin is a form of impatience

These (I mention) as the principal delinquencies in the sight of the Lord, for, to speak compendiously, every sin is ascribable to impatience. “Evil” is “impatience of good.” None immodest is not impatient of modesty; dishonest of honesty; impious of piety; unquiet of quietness.

Tertullian 
On Patience
Chapter V

The newly baptised are immediately annointed with holy oil and freed from sin

After this, when we have issued from the font, we are thoroughly anointed with a blessed unction,—(a practice derived) from the old discipline, wherein on entering the priesthood, men were wont to be anointed with oil from a horn, ever since Aaron was anointed by Moses. Whence Aaron is called “Christ,” from the “chrism,” which is “the unction;” which, when made spiritual, furnished an appropriate name to the Lord, because He was “anointed” with the Spirit by God the Father; as written in the Acts: “For truly they were gathered together in this city against Thy Holy Son whom Thou hast anointed.” Thus, too, in our case, the unction runs carnally, (i.e. on the body,) but profits spiritually; in the same way as the act of baptism itself too is carnal, in that we are plunged in water, but the effect spiritual, in that we are freed from sins.

Tertullian
On Baptism
Chapter VII

Christians are reborn through water Baptism

Happy is our sacrament of water, in that, by washing away the sins of our early blindness, we are set free and admitted into eternal life!

But we, little fishes, after the example of our ΙΧΘΥΣ Jesus Christ, are born in water, nor have we safety in any other way than by permanently abiding in water; so that most monstrous creature, who had no right to teach even sound doctrine, knew full well how to kill the little fishes, by taking them away from the water!

Tertullian
On Baptism
Chapter I

Confession is a second reserve against hell after Baptism

Therefore, since you know that after the first bulwarks of the Lord’s baptism there still remains for you, in exomologesis a second reserve of aid against hell, why do you desert your own salvation? Why are you tardy to approach what you know heals you?

Tertullian
On Repentance
Chapter XII

Confession is on the knees before other Christians who stand in Christ’s stead

In a company of two is the church; but the church is Christ. When, then, you cast yourself at the brethren’s knees, you are handling Christ, you are entreating Christ. In like manner, when they shed tears over you, it is Christ who suffers, Christ who prays the Father for mercy.

Tertullian
On Repentance
Chapter X