An “ordinary” sinner is a Christian who has lost sanctifying grace by a grievous sin. An “obdurate” sinner is one who, by repeatedly and maliciously transgressing the laws of God, has dulled his intellect and hardened his will against salutary inspirations. A man may be an habitual sinner (_consuetudinarius_) and a backslider, without being obdurate, or, which comes to the same, impenitent. Weakness is not malice, though sinful habits often beget impenitence, which is one of the sins against the Holy Ghost and the most formidable obstacle in the way of conversion. With regard to ordinary sinners, our thesis asserts that they always receive sufficient grace to avoid mortal sin and do penance. a) Experience teaches that a man falls deeper and deeper if he does not hasten to do penance after committing a mortal sin. But this is not the fault of Almighty God, who never withholds His grace; it is wholly the fault of the sinner who fails to coöperate with the proffered supernatural assistance. α) A sufficient Scriptural argument for this part of our thesis is contained in the texts cited in support of Thesis I. If it is true that God suffers no one to be tempted beyond his strength,(524) this must surely apply to Christians who have had the misfortune of committing mortal sin. St. John says that the commandments of God “are not heavy” and that faith is “the victory which overcometh the world.”(525) Faith in Christ remains in the Christian, even though he be guilty of mortal sin, and consequently if he wills, he is able, by the aid of sufficient grace, to overcome the “world,” _i.e._ the temptations arising from concupiscence,(526) and thus to cease committing mortal sins. β) As for the teaching of Tradition, St. Augustine lays down two theological principles which apply to saint and sinner alike. “God does not enjoin impossibilities,” he says, “but in His injunctions counsels you both to do what you can for yourself, and to ask His aid in what you cannot do.”(527) It follows that the sinner always receives at least the grace of prayer, which Augustine therefore calls _gratia initialis sive parva_, and of which he says that its right use ensures the _gratia magna_. The second principle is this: “_Cum lege coniuncta est gratia, quâ lex observari possit._” That is, every divine law, by special ordinance, carries with it the grace by which it may be observed. In other words, the laws of God can always be obeyed because the lawgiver never fails to grant sufficient grace to keep them.(528) b) That the sinner always receives sufficient grace to be converted, follows from the Scriptural injunction of conversion. If conversion to God is a duty, and to comply with this duty is impossible without the aid of grace,(529) the divine command obviously implies the bestowal of sufficient grace.