Holy Communion is the fulfillment of all our efforts, the goal toward which we strive, the ultimate joy of our Christian life, it is also and of necessity the source and beginning of our spiritual effort itself, the divine gift which makes it possible for us to know, to desire, and to strive for a “more perfect communion in the day without evening” of God’s Kingdom. For the Kingdom, although it has come, although it comes in the Church, is yet to be fulfilled and consummated at the end of time when God will fill all things with Himself. We know it, and we partake of it in anticipation; we partake now of the Kingdom which is still to come. We foresee and foretaste its glory and its blessedness but we are still on earth, and our entire earthly existence is thus a long and often painful journey toward the ultimate Lord’s Day.
On this journey we need help and support, strength and comfort, for the “Prince of this world” has not yet surrendered; on the contrary, knowing his defeat by Christ, he stages a last and violent battle against God to tear away from Him as many as possible. So difficult is this fight, so powerful the “gates of Hades,” that Christ Himself tells us about the “narrow way” and the few that are capable of following it. And in this fight, our main help is precisely the Body and Blood of Christ, that “essential food” which keeps us spiritually alive and, in spite of all temptations and dangers, makes us Christ’s followers.
(Alexander Schmemann, Great Lent, p. 47-48)