Institutes of the Christian Religion 3.1.1
How do we receive those benefits which the Father bestowed on his only-begotten Son—not for Christ’s own private use, but that he might enrich poor and needy men? First, we must understand that as long as Christ remains outside of us, and we are separated from him, all that he has suffered and done for the salvation of the human race remains useless and of no value for us. Therefore, to share with us what he has received from the Father, he had to become ours and to dwell within us. For this reason, he is called “our Head” [Eph 4:15], and “the first-born among many brethren” [Rom 8:29]. We also, in turn, are said to be “engrafted into him” [Rom 11:17], and to “put on Christ” [Gal 3:27]; for, as I have said, all that he possesses is nothing to us until we grow into one body with him. It is true that we obtain this by faith.
Institutes of the Christian Religion 3.11.1
Christ was given to us by God’s generosity, to be grasped and possessed by us in faith. By partaking of him, we principally receive a double grace: namely, that being reconciled to God through Christ’s blamelessness, we may have in heaven instead of a Judge a gracious Father; and secondly, that sanctified by His Spirit we may cultivate blamelessness and purity of life.