“If God is good, and prescient of the future, and able to avert evil, why did He allow man, that is to say His own image and likeness, nay more, His own substance, to be tricked by the devil and fall from obedience to the law into death? For if He had been good, and thereby unwilling that such an event should happen, and prescient, and thereby not ignorant that it would happen, and powerful, and thereby able to prevent its happening, it would certainly not have happened, being impossible under these three conditions of divine greatness. But since it did happen, the inference is certain that God must be believed to be neither good nor prescient nor powerful.”[429] The hypothesis of the existence of two Gods, by which Marcion solved this and other problems of theology, was consistently opposed by the great mass of the Christian communities. The solution which they found was almost uniformly that of the Stoics: evil is necessary for the production of moral virtue: there is no virtue where there is no choice: and man was created free to choose. It was found, in short, in the doctrine of free-will. This solution is found in Justin Martyr: “The nature of every created being is to be capable of vice and virtue: for no one of them would be an object of praise if it had not also the power of turning in the one direction or the other.”[430] It is found in Tatian: “Each of the two classes of created things (men and angels) is born with a power of self-determination, not absolutely good by nature, for that is an attribute of God alone, but brought to perfection through freedom of voluntary choice, in order that the bad man may be justly punished, being himself the cause of his being wicked, and that the righteous man may be worthily praised for his good actions, not having in his exercise of moral freedom transgressed the will of God.”[431] It is found in Irenæus: