Book Fourth, Chapter 17.2:
Pious souls can derive great confidence and delight from this sacrament, as being a testimony that they form one body with Christ, so that everything which is his they may call their own. Hence it follows, that we can confidently assure ourselves, that eternal life, of which he himself is the heir, is ours, and that the kingdom of heaven, into which he has entered, can no more be taken from us than from him; on the other hand,that we cannot be condemned for our sins, from the guilt of which he absolves us, seeing he has been pleased that these should be imputed to himself as if they were his own. This is the wondrous exchange made by his boundless goodness. Having become with us the Son of Man, he has made us with himself sons of God. By his own descent to the earth he has prepared our ascent to heaven. Having received our mortality, he has bestowed on us his immortality. Having undertaken our weakness, he has made us strong in his strength Having, submitted to our poverty, he has transferred to us his riches. Having taken upon himself the burden of unrighteousness with which we were oppressed, he has clothed us with his righteousness.