That the principle of holiness in Adam, and that which is wrought in believers, are essentially the same, I conclude from the following reasons:—

First, They are both formed after the same likeness, the image of God. “God created man in his own image; in the image of God created he him.” “Put ye on the new man, which after God is created in righteousness and true holiness.” If God be immutable in his nature, that which is created after him must be the same for substance at all times and in all circumstances. There cannot be two specifically different images of the same original.

Secondly, They are both a conformity to the same standard, the moral law. That the spirit and conduct of man in innocence was neither more nor less than a perfect conformity to this law, I suppose, will be allowed; and the same may be said of the spirit and conduct of Jesus Christ so far as he was our exemplar, or the model after which we are formed. God’s law was within his heart. It was “his meat and drink to do his will.” He went to “the end of the law for righteousness;” but it does not appear that he went beyond it. The superiority of his obedience to that of all others lay, not in his doing more than the law required, but in the dignity of his person, which stamped infinite value on every thing he did. But if such was the spirit and conduct of Christ, to whose image we are predestinated to be conformed, it must of necessity be ours. This also perfectly agrees with those Scriptural representations which describe the work of the Spirit as “writing God’s law in the heart” (Psal. 40:8; Jer. 31:33); and with those which represent the ultimate state of holiness to which we shall arrive in heaven as no more than a conformity to this law and this model: “The spirits of just men made perfect.”—“We shall be like him.”

Thirdly, The terms used to describe the one imply that it is of the same nature as the other. Conversion is expressed by a return to God, (Isa. 55:7,) which denotes a recovery to a right state of mind after a departure from him. Regeneration is called a “washing,” which expresses the restoring of the soul to purity, from which it had degenerated; and hence the same Divine operation is in the same passage called the “renewing” of the Holy Spirit.

But “this renovation,” it has been said, “is spoken of the mind, and not of a principle in the mind.”* The renewal of the mind must either be natural or moral. If the former, it would seem as if we had divested ourselves of the use of our natural faculties, and that regeneration consists in restoring them. If the latter, by the mind must be meant the disposition of the mind, or, as the Scripture speaks, “the spirit of our minds,” Eph. 4:23. But this amounts to the same thing as a principle in our minds. There is no difference between a mind being restored to a right state and condition, and a right state and condition being restored to the mind.

Fourthly, Supreme love to God, which is acknowledged to be the principle of man in innocence, would necessarily lead a fallen creature to embrace the gospel way of salvation. This is clearly intimated in our Lord’s reasoning with the Jews: “I know you, that ye have not the love of God in you. I am come in my Father’s name, and ye receive me not.” This reasoning on the contrary hypothesis was invalid: for if receiving the Messiah was that to which a principle of supreme love to God was unequal, a non-reception of him would afford no proof of its absence. They might have had the love of God in them, and yet not have received him.

The love to God which was possessed by Adam in innocence was equal to that of the holy angels. His being of the “earth, earthy,” as to his body, no more proves his inferiority to them, as to the principles of his mind, than it proves the inferiority of Christ in this respect, who before his resurrection was possessed of a natural and not a spiritual body. But it cannot be denied that the angels are capable of understanding, believing, and approving of the gospel way of salvation. It is above all others their chosen theme; “which things the angels desire to look into.” It is true they do not embrace the Messiah as their Saviour, because they do not stand in need of salvation; but give a free invitation and their principles to a being that wants a Saviour, and he would not scruple a moment about accepting it. It is not possible for a creature to love God without loving the greatest friend of God, and embracing a gospel that more than any thing tends to exalt his character; neither is it possible to love mankind with a holy and affectionate regard towards their best interests without loving the Friend of sinners, and approving of a doctrine that breathes “good-will to men.”

Excerpt from: The Gospel Worthy of All Acceptation, Part 3, “Objections Answered.”

Fuller, A. G. (1988). The Complete Works of Andrew Fuller: Controversial Publications. (J. Belcher, Ed.) (Vol. 2, pp. 370–371). Harrisonburg, VA: Sprinkle Publications.