Epistle of Barnabas
Further, what says He? “And there was a river flowing on the right, and from it arose beautiful trees; and whosoever shall eat of them shall live for ever.” This means, that we indeed descend into the water full of sins and defilement, but come up, bearing fruit in our heart, having the fear [of God] and trust in Jesus in our spirit. “And whosoever shall eat of these shall live for ever,” This means: Whosoever, He declares, shall hear you speaking, and believe, shall live for ever.
Letter to Diognetus
For in this garden a tree of knowledge and a tree of life has been planted; yet the tree of knowledge does not kill, but disobedience kills; for the scriptures state clearly how God from the beginning planted a tree [of knowledge and a tree] of life in the midst of Paradise, revealing life through knowledge; and because our first parents used it not genuinely, they were made naked by the deceit of the serpent. For neither is there life without knowledge, nor sound knowledge without true life; therefore the one (tree) is planted near the other. Discerning the force of this and blaming the knowledge which is exercised apart from the truth of the injunction which leads to life, the apostle says, “Knowledge puffs up, but charity edifies.” For the man who supposes that he knows anything without the true knowledge which is testified by the life, is ignorant, he is deceived by the serpent, because he loved not life; whereas he who with fear recognizes and desires life plants in hope expecting fruit. Let your heart be knowledge, and your life true reason, duly comprehended.
Wherefore also He drove him out of Paradise, and removed him far from the tree of life, not because He envied him the tree of life, as some venture to assert, but because He pitied him, [and did not desire] that he should continue a sinner for ever, nor that the sin which surrounded him should be immortal, and evil interminable and irremediable. But He set a bound to his [state of] sin, by interposing death, and thus causing sin to cease, putting an end to it by the dissolution of the flesh, which should take place in the earth, so that man, ceasing at length to live to sin, and dying to it, might begin to live to God.
The tree of knowledge itself was good, and its fruit was good. For it was not the tree, as some think, but the disobedience, which had death in it. For there was nothing else in the fruit than only knowledge; but knowledge is good when one uses it discreetly. But Adam, being yet an infant in age, was on this account as yet unable to receive knowledge worthily.