6:52-59 The flesh and blood of the Son of man, denote the Redeemer in the nature of man; Christ and him crucified, and the redemption wrought out by him, with all the precious benefits of redemption; pardon of sin, acceptance with God, the way to the throne of grace, the promises of the covenant, and eternal life. These are called the flesh and blood of Christ, because they are purchased by the breaking his body, and the shedding of his blood. Also, because they are meat and drink to our souls. Eating this flesh and drinking this blood mean believing in Christ. We partake of Christ and his benefits by faith. The soul that rightly knows its state and wants, finds whatever can calm the conscience, and promote true holiness, in the redeemer, God manifest in the flesh. Meditating upon the cross of Christ gives life to our repentance, love, and gratitude. We live by him, as our bodies live by our food. We live by him, as the members by the head, the branches by the root: because he lives we shall live also.
57. As the living Father hath sent me—to communicate His own life.
and I live by the Father—literally, "because of the Father"; My life and His being one, but Mine that of a Son, whose it is to be "of the Father." (See Joh 1:18; 5:26).
he that eateth me, … shall live by me—literally, "because of Me." So that though one spiritual life with Him, "the Head of every man is Christ, as the head of Christ is God" (1Co 11:3; 3:23).