We must therefore say that the very venial sins that insinuate themselves into those who have a care for earthly things, are designated by wood, hay, and stubble. For just as these are stored in a house, without belonging to the substance of the house, and can be burnt, while the house is saved, so also venial sins are multiplied in a man, while the spiritual edifice remains, and for them, man suffers fire, either of temporal trials in this life, or of purgatory after this life, and yet he is saved for ever.
Reply Obj. 1: Venial sins are not said to be built upon the spiritual foundation, as though they were laid directly upon it, but because they are laid beside it; in the same sense as it is written (Ps. 136:1): "Upon the waters of Babylon," i.e. "beside the waters": because venial sins do not destroy the edifice.
Reply Obj. 2: It is not said that everyone who builds wood, hay and stubble, shall be saved as by fire, but only those who build "upon" the "foundation." And this foundation is not dead faith, as some have esteemed, but faith quickened by charity, according to Eph. 3:17: "Rooted and founded in charity." Accordingly, he that dies in mortal sin with venial sins, has indeed wood, hay, and stubble, but not built upon the spiritual edifice; and consequently he will not be saved so as by fire.
Reply Obj. 3: Although those who are withdrawn from the care of temporal things, sin venially sometimes, yet they commit but slight venial sins, and in most cases they are cleansed by the fervor of charity: wherefore they do not build up venial sins, because these do not remain long in them. But the venial sins of those who are busy about earthly things remain longer, because they are unable to have such frequent recourse to the fervor of charity in order to remove them.
Reply Obj. 4: As the Philosopher says (De Coelo i, text. 2), "all things are comprised under three, the beginning, the middle, the end." Accordingly all degrees of venial sins are reduced to three, viz. to "wood," which remains longer in the fire; "stubble," which is burnt up at once; and "hay," which is between these two: because venial sins are removed by fire, quickly or slowly, according as man is more or less attached to them. ________________________
THIRD ARTICLE [I-II, Q. 89, Art. 3]
Whether Man Could Commit a Venial Sin in the State of Innocence?
Objection 1: It would seem that man could commit a venial sin in the state of innocence. Because on 1 Tim. 2:14, "Adam was not seduced," a gloss says: "Having had no experience of God's severity, it was possible for him to be so mistaken as to think that what he had done was a venial sin." But he would not have thought this unless he could have committed a venial sin. Therefore he could commit a venial sin without sinning mortally.
Obj. 2: Further Augustine says (Gen. ad lit. xi, 5): "We must not suppose that the tempter would have overcome man, unless first of all there had arisen in man's soul a movement of vainglory which should have been checked." Now the vainglory which preceded man's defeat, which was accomplished through his falling into mortal sin, could be nothing more than a venial sin. In like manner, Augustine says (Gen. ad lit. xi, 5) that "man was allured by a certain desire of making the experiment, when he saw that the woman did not die when she had taken the forbidden fruit." Again there seems to have been a certain movement of unbelief in Eve, since she doubted what the Lord had said, as appears from her saying (Gen. 3:3): "Lest perhaps we die." Now these apparently were venial sins. Therefore man could commit a venial sin before he committed a mortal sin.
Obj. 3: Further, mortal sin is more opposed to the integrity of the original state, than venial sin is. Now man could sin mortally notwithstanding the integrity of the original state. Therefore he could also sin venially.