Nicene and Post-Nicene Fathers, Vol. V:
A Treatise Against Two Letters of the...: Chapter 34

Chapter 34 [XVII.]—Whether There Could Be Sensual Appetite in Paradise Before the Fall.

But, while maintaining, ye Pelagians, the honourableness and fruitfulness of marriage, determine, if nobody had sinned, what you would wish to consider the life of those people in Paradise, and choose one of these four things. For beyond a doubt, either as often as ever they pleased they would have had intercourse; or they would bridle lust when intercourse was not necessary; or lust would arise at the summons of will, just at the time when chaste prudence would have perceived beforehand that intercourse was necessary; or, with no lust existing at all, as every other member served for its own work, so for its own work the organs of generation also would obey the commands of those that willed, without any difficulty. Of these four suppositions, choose which you please; but I think you will reject the two former, in which lust is either obeyed or resisted. For the first one would not be in accordance with so great a virtue, and the second not in harmony with so great a happiness. For be the idea far from us, that the glory of so great a blessedness as that should either be most basely enslaved by always following a preceding lust, or, by resisting it, should not enjoy the most abounding peace. Away, I say, with the thought that that mind should either be gratified by consenting to satisfy the concupiscence of the flesh, arising not opportunely for the sake of procreation, but with unregulated excitement, or that that quiet should find it necessary to restrain it by refusing.