James McPollin, S. J. on John 6: 51 ― 58
In this description of the eucharist as “eating flesh and drinking blood” “flesh and blood” is a Hebrew idiom for the whole person so that the sense is: sacramental communion is a personal communion (encounter) with Jesus who shares his life and the life of his Father with us (verse.53). Eucharist is a mutual “abiding,” a life of mutual presence of one person to another, a reciprocal. indwelling which does not submerge the personality of another (verses 56; cf. 15: 4 ― 6). Besides, in the eucharist Jesus continues that life-giving mission which he had received from his Father and he communicates the life he receives from the Father, who is the source of all “life” (verse 57). Therefore, Jesus, the source and bread of life, who came down from heaven and gave his life for the world, becomes a sacramental bread of life (verse 55; cf. verse 51), and, now ascended, he continues to give his own person, his “flesh and blood,” in the eucharist. Finally, the life-giving communion experienced in the eucharist is a pledge of and reaches its perfection in an eternal communion with Jesus and his Father (verses 54 and 58). Yet it is not a kind of food which gives instant and automatic claim to immortality, since its life-giving effect is assured only for the person of faith.
The two themes of this discourse, faith and the eucharist, cannot be separated for neither faith nor the eucharist are directly the focus of attention but rather both are unified in the person of Jesus who offers a living relationship through faith and sacrament. Therefore, the sacramental experience, instead of replacing faith in Jesus, expresses and confirms it, and since the whole discourse is Christ centred, it moves from Jesus’ Incarnation, Mission and death towards the eucharist. For John eucharistic faith is to believe that the same, risen, Incarnate Jesus continues to give himself to believers in a personal communion and to exercise his life-giving mission.
From: “John,” by James McPollin, S. J. Published by Michael Glazier, Inc. 1979