God Deals with Us as Individuals

God deals with us, (certainly for the most part) as individuals and not in masses. When he requires men to repent of sin, to exercise gratitude, to love, and the like, the requisition is obviously made upon them as individuals as separate from and as independent of others. It is not possible to conceive of any other way, in which obedience to the requisition can be rendered. Nor is it conceivable that the remedial effect of the atonement should be realized in any other way than this. How is it possible, if I, in my own person, have suffered the wound of sin, that a remedy, which is general and does not admit of any specific and personal appropriation, should answer my purpose? Furthermore, in dying for all, in other words, in furnishing a common salvation, available to all on their acceptance of the same. Christ necessarily died for me as an individual, since the common mass or race of men is made up of individuals, and since I am one of that common mass or race. And indeed we can have no idea of a community or mass of men, except as a congregation or collection of separate persons. In dying for the whole on certain conditions, he necessarily, therefore, on the same conditions, died for the individuals composing that whole.

It would seem to follow, then from what has been said, that the faith, which we especially need, is a personal or appropriating faith; a faith which will disintegrate us from the mass, and will enable us to take Christ home in all his offices to our own business and our own bosoms. We must be enabled to say, if we would realize the astonishing cleansing and healing efficacy there is in the gospel of God that he is MY God, of the Savior that he is MY Savior. We must be enabled to lay hold of the blessed promises, and exclaim, these are the gift of MY Father, these are the purchase of MY Savior, these are meant for ME.

It was thus, that patriarchs, prophets, and apostles believed. This was the faith of those consecrated ones, of whom the world was not worthy, recorded in the eleventh chapter of Hebrews. Hear the language of the Psalmist as an illustration of what is to be found frequently in the Scriptures. How precise, how personal, how remote from unmeaning generalities. "I will love thee, O Lord, MY strength. The Lord is MY rock, and MY fortress, and MY deliverer; MY God, MY strength, in whom I will trust; MY buckler and the horn of MY salvation, and MY high tower." And it is worthy of notice, that the first word of the Lord's prayer has this appropriating character; "OUR Father, who art in heaven." 

— The Interior of Hidden Life (2nd edition 1844), Part 1, Chapter 5.

Appropriating Faith

The usual understanding is, with the exception of those who hold strictly to a limited atonement, that our Savior has provided a common salvation, adequate to the wants of all; but available only in the case of those who exercise faith. How far this salvation will practically extend; how many individuals will avail themselves of it; why some are taken and others are left, we cannot tell; nor is it very obvious, that it is important for us to know. But certain it is, that no one will accept of the provision which is made, without faith. But what sort of faith? The answer is, It is that which can speak in the first person; that which has an appropriating power; that which can say I have sinned; I have need of this salvation; I take it home to myself. It is not enough for me to say, I believe that Christ died for others; I must also believe that he died for me individually, and accept of him as my Savior. It is not meant by this, that previous to the exercise of appropriating faith, and independently of such exercise, we have a special or particular interest in Christ, separate from and above that of others; and that appropriating faith consists in believing in this special or particular interest. An appropriating faith of this kind, and operating in this manner, might be very dangerous. It is merely meant, that out of the common interest, which is broad as the human race, we may, by means of faith, take individually that which the gospel permits us to receive and regard as our own; and that we can avail ourselves of this common interest, so as to make it personally our own, in no other way.

— The Interior or Hidden Life (2nd edition, 1844), Part 1, Chapter 5.