The Body and Blood of Christ as protection against the evil one

"Whoever eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day." [John 6:54 NIV]

"Christ says, 'My flesh is food indeed, and My blood is drink indeed. He who eats My Flesh and drinks My Blood abides in Me and I in him.' Concerning the truth of His Flesh and Blood there is no room for doubt, for now by the Lord's own declaration and by our faith it is true Flesh and true Blood. And as we are receiving these, we are made to be in Christ, and Christ in us." [St. Eligius. "Homily 8 on the Lord's Supper." 7th Century]

"As one points at the bread, it is entirely correct to say, 'this is Christ's Body!' and whoever sees this bread sees Christ's body. John has said the same thing, as we heard, that he saw the Holy Spirit when he saw the dove. So we also rightly say, 'Whoever attacks this bread attacks Christ's body, and whoever eats this bread eats Christ's body, and whoever presses this bread with his teeth or tongue presses the body of Christ with his teeth or tongue. And yet, it remains true in every respect that no one sees, grasps, eats, or crushes Christ's body like other, visible flesh is seen and crushed. For what we do to the bread is correctly and properly attributed to the body of Christ because of their sacramental union." [Luther. "The Lord's Supper." 1528]

"Jesus said to them, 'I tell you the truth, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you.'" [John 6:53 NIV]

"And he took bread, gave thanks and broke it, and gave it to them, saying, “This is my body given for you; do this in remembrance of me.”

In the same way, after the supper he took the cup, saying, “This cup is the new covenant in my blood, which is poured out for you." [Luke 22:19-20]

"Those whom we urge and encourage to fight, let us not leave them unarmed, but arm them with the protection of the Body and Blood of Christ. The Eucharist is meant to be a guard for those who receive it. If we want to make them safe against the enemy, let us arm them with the fullness of the Lord." [St. Cyprian. "Epistle 54 to Cornelius." 3rd Century]

How is the Lord's supper a guard and protection for the Christian against the evil one? It's simple; so simple that modern man with all of his complexities and empirical and rational "wisdom" cannot fathom it. It is simply Christ. There is no protection from the enemy outside of Jesus Christ and the Bread and Wine in the Lord's Supper is that very Christ. The Word become flesh has revealed to us that he has not only condescended to our mortal nature for our salvation, but now he shows us that he has gone further. He has hidden his great glory in plain bread and wine except to those who have faith. The eyes of faith see his body and blood in the supper. The eyes of faith also know that his body and blood are not separated from his divinity. To partake of his body and blood is to feed on Jesus Christ wholly. We know that he is one Christ and is not divisible because God is one and he is God; therefore, what better protection do we have than his Holy Supper? Whenever we are attacked by doubt and Satan's accusations, when the serpent tells us that God does not love us and has not forgiven us because our sins are just beyond his grace and loving-kindness, faith in the Lord's Supper shuts him up. We say, "That is a lie Satan because he gave me his Body to eat which was broken for me, and he gave me his blood to drink which was shed for the remission of my sins. One crumb of the bread of heaven and one drop of his precious blood leaves me forgiven and you utterly defeated. Go away in the name of Jesus!"

A prayer to be said in remembrance of your last reception of Holy Communion (partly taken from St. Basil's post-communion prayers):

O you who willingly give your flesh to me as food and your blood as drink, You who are a Fire, consuming the unworthy, Do not consume me, O my Creator; But rather pass through all my body parts, Into all my joints, my veins, my heart. Burn the thorns of all my transgressions, Cleanse my soul, and sanctify my thoughts. Make firm my knees and my bones; Enlighten my faith, Establish me wholly in Godly fear; Shelter me always, and guard and keep me from every soul-destroying action and word. Chasten me, purify me, and control me; Adorn me and teach me by your Holy Spirit. Make me a Tabernacle of this same Spirit only, And not the dwelling-place of sin, that from me, your habitation, through the entrance of your Holy Communion, Every evil action and every evil thought may flee as from fire. For you alone, Good Lord, are the justification and sanctification of our souls and bodies. Lord Jesus Christ, God and Master, we the whole body of your Church give thanksgiving and glorify your name forever and ever. Amen