Is the Holy Eucharist merely a symbol?

To eat somebody's flesh and to drink his blood is an old Hebraism meaning to assault and persecute

Psalm 26:2.

1 The psalm of David before he was anointed.

The Lord is my light and my salvation, whom shall I fear?

The Lord is the protector of my life; of whom shall I be afraid?

2 Whilst the wicked draw near against me, to eat my flesh.

My enemies that trouble me, have themselves been weakened, and have fallen.

Isaias 9

18 For wickedness is kindled as a fire, it shall devour the brier and the thorn: and shall kindle in the thicket of the forest, and it shall be wrapped up in smoke, ascending on high.

19 By the wrath of the Lord of hosts the land is troubled, and the people shall be as fuel for the fire: no man shall spare his brother.

20 And he shall turn to the right hand, and shall be hungry: and shall eat on the left hand, and shall not be filled: every one shall eat the flesh of his own arm: Manasses Ephraim, and Ephraim Manasses, and they together shall be against Juda.

Isaias 49

26 And I will feed thy enemies with their own flesh: and they shall be made drunk with their own blood, as with new wine: and all flesh shall know, that I am the Lord that save thee, and thy Redeemer, the mighty One of Jacob.

Michaes 3

2 You that hate good, and love evil: that violently pluck off their skins from them, and their flesh from their bones?

3 Who have eaten the flesh of my people, and have flayed their skin from off them: and have broken, and chopped their bones as for the kettle, and as flesh in the midst of the pot.

2 Kings 23:16-17 (2 samuel)

7 Saying: The Lord be merciful to me, that I may not do this: Shall I drink the blood of these men that went, and the peril of their lives? therefore he would not drink. These things did these three mighty men.

Rev 17:6 And I saw the woman drunk with the blood of the saints, and with the blood of the martyrs of Jesus. And when I had seen her, I wondered with great admiration.

Rev 17: 16 16 And the ten horns, which thou sawest on the beast, these shall hate the harlot, and shall make her desolate and naked, and shall eat her flesh, and shall burn her with fire.

Thus Matthew 26: 26-28, Mark 14:22-24, Luke 22:17-20 and 1 Cor 23-25 the words are literal and do not even give a hint of being symbolic

John 6

Then Jesus said to them: Amen, amen, I say unto you: Moses gave you not bread from heaven; but my Father giveth you the true bread from heaven.

33 For the bread of God is that which cometh down from heaven, and giveth life to the world.

34 Then they said to him: Lord, give us always this bread.

35 And Jesus said to them: I am the bread of life: *he that cometh to me, shall not hunger: and he that believeth in me, shall never thirst.

36 But I said to you, that you also have seen me, and you believe not.

37 All that the Father giveth me, shall come to me: and him that cometh to me, I will not cast out:

38 Because I came down from heaven, not to do my own will, but the will of him that sent me.

39 Now this is the will of the Father, that sent me: that of all that he hath given me, I should not lose thereof, but should raise it up again at the last day.

40 And this is the will of my Father, who sent me: that every one who seeth the Son, and believeth in him, may have everlasting life, and I will raise him up at the last day.

41 The Jews therefore murmured at him, because he had said: I am the living bread which came down from heaven.

42 And they said: *Is not this Jesus the son of Joseph, whose father and mother we know? How then saith he, I came down from heaven?

43 Jesus, therefore, answered, and said to them: Murmur not among yourselves.

44 No man can come to me, except the Father, who hath sent me, draw him: and I will raise him up at the last day.

45 It is written in the prophets: *And they shall all be taught of God. Every one that hath heard of the Father, and hath learned, cometh to me.

46 *Not that any man hath seen the Father, but he, who is of God, he hath seen the Father.

47 Amen, amen, I say unto you: He that believeth in me, hath everlasting life.

48 I am the bread of life.

49 *Your fathers did eat manna in the desert, and they died.

50 This is the bread which cometh down from heaven: that if any one eat of it, he may not die.

51 I am the living bread, which came down from heaven.

52 If any man eat of this bread, he shall live for ever: and the bread which I will give, is my flesh for the life of the world.

53 The Jews, therefore, disputed among themselves, saying: How can this man give us his flesh to eat?

54 Then Jesus said to them: Amen, amen, I say to you: Unless you eat the flesh of the Son of man, and drink his blood, you shall not have life in you.

55 He that eateth my flesh, and drinketh my blood, hath everlasting life: and I will raise him up at the last day.

56 *For my flesh, is meat indeed: and my blood, is drink indeed:

57 He that eateth my flesh, and drinketh my blood, abideth in me, and I in him.

58 As the living Father hath sent me, and I live by the Father: so he that eateth me, the same also shall live by me.

59 This is the bread that came down from heaven. Not as your fathers did eat manna, and died. He that eateth this bread, shall live for ever.

60 These things he said, teaching in the synagogue, in Capharnaum.

61 Many, therefore, of his disciples, hearing it, said: This saying is hard, and who can hear it?

62 But Jesus, knowing in himself, that his disciples murmured at this, said to them: Doth this scandalize you?

63 If then you shall see *the Son of man ascend up where he was before?

64 It is the spirit that quickeneth: the flesh profiteth nothing: the words that I have spoken to you, are spirit and life.

65 But there are some of you that believe not. For Jesus knew from the beginning who they were that did not believe, and who he was that would betray him.

66 And he said: Therefore did I say to you, that no man can come to me, unless it be given him by my Father.

67 After this many of his disciples went back: and walked no more with him.

68 Then Jesus said to the twelve: Will you also go away?

69 And Simon Peter answered him: Lord, to whom shall we go? thou hast the words of eternal life.

70 *And we have believed, and have known that thou art the Christ, the Son of God.

71 Jesus answered them: Have not I chosen you twelve: and one of you is a devil?

72 Now he meant Judas Iscariot, the son of Simon: for this same was about to betray him, whereas he was one of the twelve.

If we believe the protestants, that His words in Chapter of 6 of John are a metaphor or a symbol, then Jesus was telling the faithful the way to eternal life is to assault and persecute Him.