On the topic of original sin and a sinful nature, I have been presented with early church writer's quotes - i.e. authors before Augustine of Hippo - and, when I then looked them up, I found that in context and, in the flow of thought, they did not mean what is assumed by small quotes out of context (strung together with others).
So, for a totally impartial observation of the early Church on this matter, allow me here to quote Professor of Ecclesiastical History George Park Fisher DD LLD in his work History of Christian Doctrine (1896 - Pages 164-165 - NB: like with the early church writers, the KJV, YLT, etc, 70 years following the death of an author, copyright no longer remains applicable and, for this same reason, I have also placed no copyright on this web page): please find these "[ ]" reveal my [additions]:
A defining characteristic of the Greek anthropology [the early Church Greek Writers/Fathers] is the uniformity and emphasis with which the freedom of the will, and its continued liberty after the incoming of sin, is asserted.
The Fathers are agreed in tracing the sinfulness of mankind to the voluntary transgression of Adam. They agree in teaching that this transgression brought the race of mankind under the dominion of Satan. The discernment [by man] of God and of divine things became clouded. Sensual propensities gained an augmented force. Nature and the revealed law were ineffectual for man's recovery. This is achieved only through the incarnate Logos, the source of man's original endowment of reason and spiritual perception. The baneful act of sin in the individual goes forward gradually, from one degree of depravation to another. This is the definition of Athanasius. The sum of the consequences of Adam's fall is made to consist in the dominion of Satan, in mortality, and in the increased exposure to the seductions of evil.
Yet by the Greek Fathers the reign of sin in mankind is depicted in strong colors. This is true, for example, of Athanasius; and there are passages in Gregory of Nyssa which, were they all that this author says on the subject, might lead us to infer that he held to an inherited sinful depravity, involving guilt. But such was not the fact. When Athanasius says that as man can turn to things good, so he can turn away from the same1, and when Methodius says that "sin is an act of personal freedom, without which there is neither sin nor virtue, neither reward nor punishment," they express the common conviction of the Greek theologians.
The sharp distinction between nature and will is drawn out by Athanasius in a passage having direct reference to the generation of the Logos.2 Chrysostom, commenting on the 51st Psalm, says that with the first sin a path was opened for the progress of sin over the whole race. Adam and Eve have generated children who are mortal, and subject to the influence of passion and appetite. The reason is obliged to war against these, and wins glory by victory or shame by defeat. In reference to Roman 5:19, Chrysostom says that a man would not deserve punishment, "if it were not from his own self that he became a sinner." When the posterity of Adam are called sinners, it means that they share in Adam's punishment by being condemned to death. If by the question is asked, how is this just, the answer is given that death and the calamities akin to it are benefit to us, for we get from them "numberless grounds" for being good. The present life is a "sort of school," and made such by the discipline of suffering.
Cyril of Jerusalem (c.313-386AD) says explicitly, "we come sinless into the world; we sin now voluntarily."3 Athanasius goes so far as to say that there have been many saints who have been free from all sin. Jeremiah and John the Baptist are mentioned as examples. Gregory of Nyssa, Gregory of Nazianzum, Basil, and Chrysostom pronounce new-born children free from sin.
It may seem difficult to reconcile passages like these just referred to with other utterances found in the same teachers. In passages of a different tenor, however, they have in mind a corruption that does not involve guilt. Nevertheless, it is vain to attempt to reduce the teaching of the Greek Fathers, even the most eminent of them, to entire logical consistency.
As might be expected, the renewal of the soul is made to be the result of the factors, divine grace and the exertion of man's free-will. As a rule, the exertion of free-will, human efforts in a right direction, precede the divine aid, and render men worthy of it. It is a doctrine of synergism. God and man cooperate. The lack of a distinct and self-consistent separation of that which is natural, and that which is an added supernatural gift, in the soul, leads in some cases to a seeming reduction of the agency of the divine factor in regeneration. This remark applies to Athanasius.4
In harmony with the foregoing views as to human freedom and responsibility, conditional predestination is the doctrine inculcated [persistently taught] by the Greek Fathers.
[Emphasis in last 2 paragraphs added]
These are the Notes in Fisher's History of Christian Doctrine pages 164-165
Only the number of the notes differ as Fisher's are per page and I quote several pages.
1Cont. Gent. 4.
[the previous note was "Adv. Ar. Orat. II. § 66 sq." Page 163]
2C. Ar. III. 66
3Cat. IV. 19; see also 21
4See the remarks of Harnack, DG. II. 146 sq.