This is how the Catechism defines it:
**1374 **The mode of Christ’s presence under the Eucharistic species is unique. It raises the Eucharist above all the sacraments as “the perfection of the spiritual life and the end to which all the sacraments tend.” In the most blessed sacrament of the Eucharist “the body and blood, together with the soul and divinity, of our Lord Jesus Christ and, therefore, the whole Christ is truly, really, and substantially contained.” “This presence is called ‘real’ - by which is not intended to exclude the other types of presence as if they could not be ‘real’ too, but because it is presence in the fullest sense: that is to say, it is a *substantial *presence by which Christ, God and man, makes himself wholly and entirely present.”
Yeah I already read that, and it didn’t really help me. I’m trying to understand what Augustine of Hippo meant, when he said in his
Exposition on Psalm 99 (chapter 8):
And because He walked here in very flesh, and gave that very flesh to us to eat for our salvation; and no one eateth that flesh, unless he hath first worshipped: we have found out in what sense such a footstool of our Lord’s may be worshipped, and not only that we sin not in worshipping it, but that we sin in not worshipping. But doth the flesh give life? Our Lord Himself, when He was speaking in praise of this same earth, said, “It is the Spirit that quickeneth, the flesh profiteth nothing.” . . . But when our Lord praised it, He was speaking of His own flesh, and He had said, “Except a man eat My flesh, he shall have no life in him.” Some disciples of His, about seventy? were offended, and said, “This is an hard saying, who can hear it?” And they went back, and walked no more with Him. It seemed unto them hard that He said, “Except ye eat the flesh of the Son of Man, ye have no life in you:” they received it foolishly, they thought of it carnally, and imagined that the Lord would cut off parts from His body, and give unto them; and they said, “This is a hard saying.” It was they who were hard, not the saying; for unless they had been hard, and not meek, they would have said unto themselves, He saith not this without reason, but there must be some latent mystery herein. They would have remained with Him, softened, not hard: and would have learnt that from Him which they who remained, when the others departed, learnt. For when twelve disciples had remained with Him, on their departure, these remaining followers suggested to Him, as if in grief for the death of the former, that they were offended by His words, and turned back. But He instructed them, and saith unto them, “It is the Spirit that quickeneth, but the flesh profiteth nothing; the words that I have spoken unto you, they are spirit, and they are life.” Understand spiritu ally [sic] what I have said; ye are not to eat this body which ye see; nor to drink that blood which they who will crucify Me shall pour forth. I have commended unto you a certain mystery; spiritually understood, it will quicken. Although it is needful that this be visibly celebrated, yet it must be spiritually understood.
I think my original definition above is wrong, but I’m simply trying to understand the teaching better.
