Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that man can know that he has grace. For grace by its physical reality is in the soul. Now the soul has most certain knowledge of those things that are in it by their physical reality, as appears from Augustine (Gen. ad lit. xii, 31). Hence grace may be known most certainly by one who has grace.

Objection 2: Further, as knowledge is a gift of God, so is grace. But whoever receives knowledge from God, knows that he has knowledge, according to Wis. 7:17: The Lord "hath given me the true knowledge of the things that are." Hence, with equal reason, whoever receives grace from God, knows that he has grace.

Objection 3: Further, light is more knowable than darkness, since, according to the Apostle (Eph. 5:13), "all that is made manifest is light," Now sin, which is spiritual darkness, may be known with certainty by one that is in sin. Much more, therefore, may grace, which is spiritual light, be known.

Objection 4: Further, the Apostle says (1 Cor. 2:12): "Now we have received not the Spirit of this world, but the Spirit that is of God; that we may know the things that are given us from God." Now grace is God's first gift. Hence, the man who receives grace by the Holy Spirit, by the same Holy Spirit knows the grace given to him.

Objection 5: Further, it was said by the Lord to Abraham (Gn. 22:12): "Now I know that thou fearest God," i.e. "I have made thee know." Now He is speaking there of chaste fear, which is not apart from grace. Hence a man may know that he has grace.

On the contrary, It is written (Eccles. 9:1): "Man knoweth not whether he be worthy of love or hatred." Now sanctifying grace maketh a man worthy of God's love. Therefore no one can know whether he has sanctifying grace.

I answer that, There are three ways of knowing a thing: first, by revelation, and thus anyone may know that he has grace, for God by a special privilege reveals this at times to some, in order that the joy of safety may begin in them even in this life, and that they may carry on toilsome works with greater trust and greater energy, and may bear the evils of this present life, as when it was said to Paul (2 Cor. 12:9): "My grace is sufficient for thee."

Secondly, a man may, of himself, know something, and with certainty; and in this way no one can know that he has grace. For certitude about a thing can only be had when we may judge of it by its proper principle. Thus it is by undemonstrable universal principles that certitude is obtained concerning demonstrative conclusions. Now no one can know he has the knowledge of a conclusion if he does not know its principle. But the principle of grace and its object is God, Who by reason of His very excellence is unknown to us, according to Job 36:26: "Behold God is great, exceeding our knowledge." And hence His presence in us and His absence cannot be known with certainty, according to Job 9:11: "If He come to me, I shall not see Him; if He depart I shall not understand." And hence man cannot judge with certainty that he has grace, according to 1 Cor. 4:3,4: "But neither do I judge my own self . . . but He that judgeth me is the Lord."

Thirdly, things are known conjecturally by signs; and thus anyone may know he has grace, when he is conscious of delighting in God, and of despising worldly things, and inasmuch as a man is not conscious of any mortal sin. And thus it is written (Apoc. 2:17): "To him that overcometh I will give the hidden manna . . . which no man knoweth, but he that receiveth it," because whoever receives it knows, by experiencing a certain sweetness, which he who does not receive it, does not experience. Yet this knowledge is imperfect; hence the Apostle says (1 Cor. 4:4): "I am not conscious to myself of anything, yet am I not hereby justified," since, according to Ps. 18:13: "Who can understand sins? From my secret ones cleanse me, O Lord, and from those of others spare Thy servant."

Reply to Objection 1: Those things which are in the soul by their physical reality, are known through experimental knowledge; in so far as through acts man has experience of their inward principles: thus when we wish, we perceive that we have a will; and when we exercise the functions of life, we observe that there is life in us.

Reply to Objection 2: It is an essential condition of knowledge that a man should have certitude of the objects of knowledge; and again, it is an essential condition of faith that a man should be certain of the things of faith, and this, because certitude belongs to the perfection of the intellect, wherein these gifts exist. Hence, whoever has knowledge or faith is certain that he has them. But it is otherwise with grace and charity and such like, which perfect the appetitive faculty.

Reply to Objection 3: Sin has for its principal object commutable good, which is known to us. But the object or end of grace is unknown to us on account of the greatness of its light, according to 1 Tim. 6:16: "Who . . . inhabiteth light inaccessible."

Reply to Objection 4: The Apostle is here speaking of the gifts of glory, which have been given to us in hope, and these we know most certainly by faith, although we do not know for certain that we have grace to enable us to merit them. Or it may be said that he is speaking of the privileged knowledge, which comes of revelation. Hence he adds (1 Cor. 2:10): "But to us God hath revealed them by His Spirit."

Reply to Objection 5: What was said to Abraham may refer to experimental knowledge which springs from deeds of which we are cognizant. For in the deed that Abraham had just wrought, he could know experimentally that he had the fear of God. Or it may refer to a revelation.

Articulus 5

Argumentum 1

Ad quintum sic proceditur. Videtur quod homo possit scire se habere gratiam. Gratia enim est in anima per sui essentiam.

Sed certissima cognitio animae est eorum quae sunt in anima per sui essentiam; ut patet per Augustinum, XII super Gen. Ad litt..

Ergo gratia certissime potest cognosci a deo qui gratiam habet.

Argumentum 2

Praeterea, sicut scientia est donum dei, ita et gratia.

Sed qui a deo scientiam accipit, scit se scientiam habere; secundum illud Sap. VII, dominus dedit mihi horum quae sunt veram scientiam.

Ergo pari ratione qui accipit gratiam a deo, scit se gratiam habere.

Argumentum 3

Praeterea, lumen est magis cognoscibile quam tenebra, quia secundum apostolum, ad Ephes. V, omne quod manifestatur, lumen est.

Sed peccatum, quod est spiritualis tenebra, per certitudinem potest sciri ab eo qui habet peccatum.

Ergo multo magis gratia, quae est spirituale lumen.

Argumentum 4

Praeterea, apostolus dicit, I ad Cor. II, nos autem non spiritum huius mundi accepimus, sed spiritum qui a deo est, ut sciamus quae a deo donata sunt nobis.

Sed gratia est praecipuum donum dei.

Ergo homo qui accepit gratiam per spiritum sanctum, per eundem spiritum scit gratiam esse sibi datam.

Argumentum 5

Praeterea, Gen. XXII, ex persona domini dicitur ad Abraham, nunc cognovi quod timeas dominum, idest, cognoscere te feci.

Loquitur autem ibi de timore casto, qui non est sine gratia.

Ergo homo potest cognoscere se habere gratiam.

Sed Contra

Sed contra est quod dicitur Eccle. IX, nemo scit utrum sit dignus odio vel amore.

Sed gratia gratum faciens facit hominem dignum dei amore.

Ergo nullus potest scire utrum habeat gratiam gratum facientem.

Corpus

Respondeo dicendum quod tripliciter aliquid cognosci potest.

Uno modo, per revelationem. Et hoc modo potest aliquis scire se habere gratiam. Revelat enim deus hoc aliquando aliquibus ex speciali privilegio, ut securitatis gaudium etiam in hac vita in eis incipiat, et confidentius et fortius magnifica opera prosequantur, et mala praesentis vitae sustineant, sicut Paulo dictum est, II ad Cor. XII, sufficit tibi gratia mea.

Alio modo homo cognoscit aliquid per seipsum, et hoc certitudinaliter. Et sic nullus potest scire se habere gratiam. Certitudo enim non potest haberi de aliquo, nisi possit diiudicari per proprium principium, sic enim certitudo habetur de conclusionibus demonstrativis per indemonstrabilia universalia principia; nullus autem posset scire se habere scientiam alicuius conclusionis, si principium ignoraret. Principium autem gratiae, et obiectum eius, est ipse deus, qui propter sui excellentiam est nobis ignotus; secundum illud iob XXXVI, ecce, deus magnus, vincens scientiam nostram.

Et ideo eius praesentia in nobis vel absentia per certitudinem cognosci non potest; secundum illud iob IX, si venerit ad me, non videbo eum, si autem abierit, non intelligam.

Et ideo homo non potest per certitudinem diiudicare utrum ipse habeat gratiam; secundum illud I ad Cor. IV, sed neque meipsum iudico, qui autem iudicat me, dominus est.

Tertio modo cognoscitur aliquid coniecturaliter per aliqua signa. Et hoc modo aliquis cognoscere potest se habere gratiam, inquantum scilicet percipit se delectari in deo, et contemnere res mundanas; et inquantum homo non est conscius sibi alicuius peccati mortalis.

Secundum quem modum potest intelligi quod habetur Apoc. II, vincenti dabo manna absconditum, quod nemo novit nisi qui accipit, quia scilicet ille qui accipit, per quandam experientiam dulcedinis novit, quam non experitur ille qui non accipit.

Ista tamen cognitio imperfecta est.

Unde apostolus dicit, I ad Cor. IV, nihil mihi conscius sum, sed non in hoc iustificatus sum.

Quia ut dicitur in Psalmo XVIII, delicta quis intelligit? ab occultis meis munda me, domine.

Ad 1

Ad primum ergo dicendum quod illa quae sunt per essentiam sui in anima, cognoscuntur experimentali cognitione, inquantum homo experitur per actus principia intrinseca, sicut voluntatem percipimus volendo, et vitam in operibus vitae.

Ad 2

Ad secundum dicendum quod de ratione scientiae est quod homo certitudinem habeat de his quorum habet scientiam, et similiter de ratione fidei est quod homo sit certus de his quorum habet fidem. Et hoc ideo, quia certitudo pertinet ad perfectionem intellectus, in quo praedicta dona existunt.

Et ideo quicumque habet scientiam vel fidem, certus est se habere. Non est autem similis ratio de gratia et caritate et aliis huiusmodi, quae perficiunt vim appetitivam.

Ad 3

Ad tertium dicendum quod peccatum habet pro principio et pro obiecto bonum commutabile, quod nobis est notum. Obiectum autem vel finis gratiae est nobis ignotum, propter sui luminis immensitatem; secundum illud I ad Tim. Ult., lucem habitat inaccessibilem.

Ad 4

Ad quartum dicendum quod apostolus ibi loquitur de donis gloriae, quae sunt nobis data in spe, quae certissime cognoscimus per fidem; licet non cognoscamus per certitudinem nos habere gratiam, per quam nos possumus ea promereri. Vel potest dici quod loquitur de notitia privilegiata, quae est per revelationem. Unde subdit, nobis autem revelavit deus per spiritum sanctum.

Ad 5

Ad quintum dicendum quod illud etiam verbum Abrahae dictum, potest referri ad notitiam experimentalem, quae est per exhibitionem operis.

In opere enim illo quod fecerat Abraham, cognoscere potuit experimentaliter se dei timorem habere.

Vel potest etiam ad revelationem referri.