Except when He says, Matthew 26:29 "I tell you I will not drink again of this fruit of the vine until that day when I drink it new with you in my Father’s kingdom."
And not to mention that Peter in Acts says, (Acts 10:14-16) " But Peter said, "By no means, Lord; for I have never eaten anything that is common or unclean." And the voice came to him again a second time, "What God has made clean, do not call common." This happened three times, and the thing was taken up at once to heaven."
Peter had to know that what Jesus meant was symbolic. If Peter understood it to be literal blood, being an observant Jew, he NEVER would have partook of the cup. And *IF* he had thought that the cup was the literal blood of Christ, then he lied to God in Acts 10; three times.
If Peter understood it to be literal blood, being an an observant Jew and follower of the Messiah, he would do whatever the Messiah Christ asked of him and would have partook of the cup.
And *IF* he had thought that the cup was the literal blood of the Messiah Christ, then he would not insult God by referring to the Messiah’s blood as unclean in his dialogue with the Voice in Acts 10 (and he certainly would not insult God 3 times).
In fact one can use your own citation against the position you take by noting that your comments violate the Voices admonition “Do not call anything impure that God has made clean.” For it was God, the Messiah Himself, who made the flesh and blood of the Last Supper clean - in fact, spotless.