Man in the state of justification, they argue, is endowed with sanctifying grace, the supernatural habits of faith, hope, and charity, and the infused moral virtues, and consequently possesses all those qualifications which are necessary to enable him to perform salutary acts with the supernatural concurrence of God. Why should the will, thus supernaturally equipped, require the aid of additional actual graces to enable it to perform strictly supernatural, and therefore salutary, actions?(353) We reply: The necessity of actual grace in the state of justification is so clearly taught by divine Revelation that no theological theory is tenable which denies it. Besides, the objection we have briefly summarized disregards some very essential considerations, _e.g._ that there remains in man, even after justification, concupiscence, which is accompanied by a certain weakness that requires at least the _gratia sanans sive medicinalis_ to heal it.(354) Furthermore, a quiescent _habitus_ cannot set itself in motion, but must be determined from without; that is to say, in our case, it must be moved by the _gratia excitans_ to elicit supernatural thoughts and to will supernatural acts. Just as a seed cannot sprout without the aid of appropriate stimuli, so sanctifying grace is incapable of bearing fruit unless stimulated by the sunshine and moisture of actual graces. Man may perform purely natural acts even though he be in the supernatural state of grace; hence if any particular act of his is to be truly supernatural and conducive to eternal salvation, God must lend His special aid.(355) *Thesis IV: Except by a special privilege of divine grace, man, even though he be in the state of sanctifying grace, is unable to avoid venial sin throughout life.* This is likewise _de fide_. Proof. The Pelagians held that man is able to avoid sin, nay to attain to absolute impeccability,(356) without supernatural assistance. Against this error the Second Council of Mileve (A. D. 416) defined: “It likewise hath pleased [the holy Synod] that whoever holds that the words of the Our Father: ‘Forgive us our trespasses,’ when pronounced by saintly men, are pronounced in token of humility, but not truthfully, should be anathema.”(357) Still more to the point is the following declaration of the Council of Trent: “If any one saith that a man once justified ... is able, during his whole life, to avoid all sins, even those that are venial, except by a special grace from God, as the Church holds in regard of the Blessed Virgin; let him be anathema.”(358) To obtain a better understanding of this Tridentine definition it will be well to ponder the following considerations: