The question concerning the efficient cause of conversion has been answered in three different ways. In the first place, it has been said that man himself is the cause of his conversion (Pelagianism). Again, it has been claimed that both God and man cooperate in bringing about the conversion of man, the sinner either beginning the work and God completing it (Semi-Pelagianism, Arminianism), or God making the beginning and the enlightened and awakened sinner himself completing it (synergism).
With regard to Semi-Pelagianism and synergism the Formula of Concord says Epitome, II, 10.11 : “We reject also the error of the Semi-Pelagians, who teach that man by his own powers can make a beginning of his conversion, but without the grace of the Holy Ohost cannot complete it; also, when it is taught that, although man by his free will before regeneration is too weak to make a beginning and by his own powers to turn himself to God and from the heart to be obedient to God, yet, if the Holy Ghost, by the preaching of the Word, has made a beginning and therein offered His grace, then the will of man from its own natural powers can add something synergism, though little and feebly, to this end, can help and cooperate, qualify and prepare itself for grace, and embrace and accept it, and believe the Gospel.” According to this clear, decisive statement the Lutheran Confession on the basis of Scripture rejects both Pelagianism and synergism and supplies a third answer to the question concerning man’s conversion, namely, God alone is the efficient Cause of conversion (divine monergism), while the sinner (subiectum convertendum) conducts himself mere, or pure, passive.
Of this the Formula of Concord says (Thor. Decl., II, 87): “The conversion of our corrupt will, which is nothing else than a resuscitation of its spiritual death, is only and solely the work of God, just as the resuscitation in the resurrection of the body must be ascribed to God alone, as has been fully set forth above and proved by manifest testimonies of Holy Scripture.” The doctrine of conversion here set forth is that of Holy Scripture, which teaches expressly that, if a sinner is converted, this is due, not to any efforts of his own, but alone to the effectual working of divine grace, Eph. 1, 19. The Scriptural proof for this truth may be stated as follows: —
a. Scripture positively ascribes conversion, or the engendering of faith in man’s heart, exclusively to God, John 6, 44; Rom. 1, 5—7; Col. 1, 12. 13; in particular, to His grace, Phil. 1, 29; Eph. 2, 8. 9, and omnipotent power, Eph. 1, 19; 2 Cor. 4, 6. Moreover, it depicts conversion as a new birth from God, John 1, 12. 13; 1 John 5, 1, or a spiritual resurrection, Col. 2, 12. 13. All these passages describe conversion as an act of divine grace (monergism) and exclude from it man’s operation or cooperation.
b. Scripture expressly denies to unconverted man the power to know or to believe the Gospel, 1 Cor. 2, 14; John 6, 44, and charges him with the offense of resisting the good and gracious will of God, which earnestly desires his regeneration, up to the very moment when he is converted, 1 Cor. 2, 14; Rom. 8, 7. Hence also these passages describe conversion as an act of divine grace and exclude from it man’s operation or cooperation. Both positively and negatively Scripture therefore declares itself for divine monergism and against all forms of Pelagianism and synergism. Luther: “We rightly honor God if we acknowledge that we are not saved by our merits and put our trust in His mercy.” (St. L., XI, 2217.)
That God alone is the efficient Cause of conversion is clear also from the very nature of conversion (forma conversion). As we have seen, conversion consists essentially in this, that the terrified and penitent sinner believes in Christ and with such faith indeed as strenuously repudiates all work-righteousness and trusts for salvation in nothing else than in the merits of Christ. But such faith in Christ implies a complete and absolute change of the sinner’s heart and mind. By nature man is addicted to work-righteousness and desires no other way of salvation than that of relying on his good works.
But if that is the case, then the change in his heart by which he repudiates all works and clings alone to Christ’s merits cannot come from man; for by nature he detests and opposes the Gospel way of salvation, 1 Cor. 2, 8. 14; 1, 23. The change must therefore be of God, as indeed it is. The Apology writes correctly (Art. III, 144 ff.): “This opinion of the Law inheres by nature in men’s minds; neither can it be expelled, unless when we are divinely taught. But the mind must be recalled from such carnal opinions to the Word of God.”
Against the Scriptural doctrine that God alone works and effects conversion it has been claimed that man by nature is indeed unable to believe the Gospel, to desist from opposing the Holy Spirit, to prepare himself for grace, and to observe a proper conduct toward the calling and sanctifying operation of God; but this, it is claimed, he certainly can do as soon as he is endowed with spiritual powers.
To this objection we reply that, if a person is able to do these spiritual works with powers granted to him by the Holy Ghost, he is already converted; for in that case his heart is completely changed, his will is conformed to God and divine things, his mind no longer regards the Gospel as foolishness, but as divine wisdom, and the crucified Savior, the world’s only spiritual Hope, is no longer a stumbling-block to him. In other words, in that case man exhibits every characteristic of a converted person, or of a believer.
Of the unregenerate, or unconverted, the Formula of Concord rightly declares (Thor. Decl., II, 7): “The natural free will according to its perverted disposition and nature is strong and active only with respect to what is displeasing and contrary to God.” Of conversion it says ibid., § 83: “Conversion is such a change through the ojoration of the Holy Ghost in the intellect, will, and heart of man that by this operation of the Holy Ghost man can accept the offered grace.” Our Confession thus supports the Scriptural doctrine that the endowment of a person with spiritual powers is the very essence of conversion. (Donatio virium spiritualium est ipsa conversio.)
That God alone is the efficient Cause of conversion is the proper scope of Article II of the Formula of Concord. As it correctly points out, man with respect to his conversion is not active, but pure passivus (purely passive), that is, “he does nothing whatever towards it, but only suffers what God works in him” (Thor. Decl., II, 89). (Hominem in conversions sua pure passive sese habere, id est, pati id, quod Deus in ipso aqit. . . .) In other words, man’s capacity for conversion must be regarded as entirely passive (capacitas passiva, non capacitas activa). His spiritual cooperation therefore begins only after he has been converted.
Our Confession says (Thor. Decl., II, 90): “The intellect and will of the unregenerate man are nothing else than subiectum convertendum, that is, that which is to be converted, it being the intellect and will of a spiritually dead man in whom the Holy Ghost works conversion and renewal, toward which work man’s will that is to be converted does nothing, but suffers God alone to work in him, until he is regenerate; and then he works also with the Holy Ghost that which is pleasing to God in other good works that follow.”
Hence there are not three efficient causes of conversion (tres causae efficientes conversion), namely, the Holy Spirit, the Word, and the assenting will of man, as Melanehthon and his synergistic followers erroneously affirmed, but only two, the Holy Spirit and the Word of God. In his conversion man is like a block or stone, indeed, much worse than a block or stone, since by reason of his natural enmity against God, 1 Cor. 2, 14; Rom. 8, 7, he resists the operations of the Holy Spirit until he is converted.
The Formula of Concord says of this (Thor. Decl., II, 59) : “A stone or block does not resist the person who moves it, nor does it understand, and is sensible of, what is being done with it, as man with his will so long resists God the Lord until he is converted. . . . He can do nothing whatever towards his conversion . . . and is in this respect much worse than a stone and block; for he resists the Word and will of God, until God awakens him from the death of sin, enlightens and renews him.”
It is true, conversion does not take place without a complete inner change of the heart; for the sinner experiences the terrors of conscience (terrores conscientiae), and through the operation of the Holy Spirit he believes the Gospel, which formerly, in his state of unbelief, he rejected. But neither the effects of the Law upon his heart nor his faith in the Gospel promises are due to his own efforts; for over against both the Law and the Gospel he is purely passive and only suffers “what God works in him” ibid., §89. “Man of himself, or from his natural powers, cannot do anything or help towards his conversion, and . . . conversion is not only in part, but altogether an operation, gift, present, and work of the Holy Ghost alone, who accomplishes and effects it by His power and might, through the Word.” (Ibid.)
In these clear and unmistakable words the Formula of Concord defends divine monergism against synergism. Its doctrine is:
"Conversion is alone the work of the Holy Ghost, who operates by means of the Word of God.” (Solus Deus convertit hominem.)
To the charge that our Confession rather overemphasizes this point, we reply that the writers of the Formula of Concord were fully persuaded that the adoption of synergism by the Lutheran Church would completely destroy the foundation of the Reformation and lead the purified Church back to Pelagianism, the fundamental error of the Papacy. A synergistic Lutheran Church, they perceived, could not teach the sola gratia in its Scriptural truth and purity. Hence, when they warded off the attacks of the synergists, they fought against foes who "flew at the throat” of Christianity. (Cp. Luther's words addressed to Erasmus: "Unus tu et solus cardinem rerum vidisti et ipsum iugulum petisti.” Also Dr. P. Bente’s statement: "Genuine Lutheranism would have been strangled if synergism had emerged victorious from this great controversy of grace versus free will.” Concordia Triglotta, Histor. Introd., p. 128.)