Christ saves the entire man — body and soul

Now, since he consists of two parts, body and soul, the point to be inquired into is, in which of these two man would seem to have been lost? If in his body, then it is his body, not his soul, which is lost. What, however, is lost, the Son of man saves. The body, therefore, has the salvation. If, (on the other hand,) it is in his soul that man is lost, salvation is designed for the lost soul; and the body which is not lost is safe. If, (to take the only other supposition,) man is wholly lost, in both his natures, then it necessarily follows that salvation is appointed for the entire man; and then the opinion of the heretics is shivered to pieces, who say that there is no salvation of the flesh. And this affords a confirmation that Christ belongs to the Creator, who followed the Creator in promising the salvation of the whole man.

Tertullian
The Five Books Against Marcion, Book IV
Chapter XXXVII

Christ regenerated our lives through incarnation and resurrection

…none but Christ could become incarnate by being born of the flesh in order that by His own nativity He might regenerate our birth, and might further by His death also dissolve our death, by rising again in that flesh in which, that He might even die, He was born.

Tertullian
The Five Books Against Marcion, Book III
Chapter IX

Our free will plays a part in our salvation

And thus it comes to pass, that even now also, the same human being, the same substance of his soul, the same condition as Adam’s, is made conqueror over the same devil by the self-same liberty and power of his will, when it moves in obedience to the laws of God.

Tertullian
The Five Books Against Marcion, Book II
Chapter VIII

Baptism forgives sins, delivers from death and regenerates man

Oh, what a god is this! everywhere perverse; nowhere rational; in all cases vain; and therefore a nonentity!—in whose state, and condition, and nature, and every appointment, I see no coherence and consistency; no, not even in the very sacrament of his faith! For what end does baptism serve, according to him? If the remission of sins, how will he make it evident that he remits sins, when he affords no evidence that he retains them? Because he would retain them, if he performed the functions of a judge. If deliverance from death, how could he deliver from death, who has not delivered to death? For he must have delivered the sinner to death, if he had from the beginning condemned sin. If the regeneration of man, how can he regenerate, who has never generated? For the repetition of an act is impossible to him, by whom nothing any time has been ever done. If the bestowal of the Holy Ghost, how will he bestow the Spirit, who did not at first impart the life? For the life is in a sense the supplement of the Spirit. He therefore seals man, who had never been unsealed in respect of him; washes man, who had never been defiled so far as he was concerned; and into this sacrament of salvation wholly plunges that flesh which is beyond the pale of salvation!

Tertullian
The Five Books Against Marion, Book I
Chapter XXVIII

Salvation can be lost

And what will it be to be cast away, but to lose that which a man was in the way of obtaining, were it not for his rejection—that is, his salvation?  Therefore his being cast away will involve the forfeiture of salvation; and this sentence cannot possibly be passed upon him, except by an angry and offended authority, who is also the punisher of sin—that is, by a judge.

Tertullian
The Five Books Against Marcion, Book I
Chapter XXVIII

Holy orders mentioned. Salvation can be lost.

But what if a bishop, if a deacon, if a widow, if a virgin, if a doctor, if even a martyr, have fallen from the rule (of faith), will heresies on that account appear to possess the truth? Do we prove the faith by the persons, or the persons by the faith?  No one is wise, no one is faithful, no one excels in dignity, but the Christian; and no one is a Christian but he who perseveres even to the end.

Tertullian
Against Marcion
The Prescription Against Heretics
Chapter III

We will be raised in our own bodies to be judged and sentenced irrevocably

Accordingly, God’s judgment will be more full and complete, because it will be pronounced at the very last, in an eternal irrevocable sentence, both of punishment and of consolation, (on men whose) souls are not to transmigrate into beasts, but are to return into their own proper bodies. And all this once for all, and on “that day, too, of which the Father only knoweth;” (only knoweth,) in order that by her trembling expectation faith may make full trial of her anxious sincerity, keeping her gaze ever fixed on that day, in her perpetual ignorance of it, daily fearing that for which she yet daily hopes.

Tertullian
A Treatise on the Soul
Chapter XXXIII

Salvation can’t be earned

He who has compared human things with divine will require no further arguments on these points. And yet the latter opinion ought to be discussed, that God conferred divine honors 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 honor; except it be, that there is now no longer such a place for any one to attain to. Let us grant that anciently men may have deserved heaven by reason of their great merits. Then let us consider whether there really was such merit. Let the man who alleges that it did exist declare his own view of merit.  Since the actions of men done in the very infancy of time are a valid claim for their deification, you consistently admitted to the honor the brother and sister who were stained with the sin of incest—Ops and Saturn.

Tertullian
Ad Nationes, Book II
Chapter XIII

God inspires those who choose him

For, evidently in honor of their excellent nature and their holy choice, he inspires those who have made choice of a good life with strength for the rest of their salvation; exhorting some, and helping others, who of themselves have become worthy.

Clement of Alexandria
The Stromata, Book VII
Chapter VII