John 6:51

Is my flesh, which I will give, etc. - Our Lord explains his meaning more fully, in these words, than he had done before. Having spoken so much of the bread which feeds and nourishes the soul, and preserves from death, the attention of his hearers was fixed upon his words, which to them appeared inexplicable; and they desired to know what their meaning was. He then told them that the bread meant his flesh, (his life), which he was about to give up; to save the life of the world. Here our Lord plainly declares that his death was to be a vicarious sacrifice and atonement for the sin of the world; and that, as no human life could be preserved unless there was bread (proper nourishment) received, so no soul could be saved but by the merit of his death. Reader, remember this: it is one of the weightiest, and one of the truest and most important sayings in the book of God.

The bread that I will give is by flesh - That is, his body would be offered as a sacrifice for sin, agreeably to his declaration when he instituted the Supper: "This is my body which is broken for you," 1 Corinthians 11:24.

Life of the world - That sinners might, by his atoning sacrifice, be recovered from spiritual death, and be brought to eternal life. The use of the word world hero shows that the sacrifice of Christ was full free ample, and designed for all men, as it is said in 1 John 2:2, "He is the propitiation for our sins, and not for ours only, but also for the sins of the whole world." In this verse Jesus introduces the subject of his death and atonement. It may be remarked that in the language which he used the transition from bread to his flesh would appear more easy than it does in our language. The same word which in Hebrew means "bread," in the Syriac and Arabic means also "flesh."

6:51 If any eat of this bread - That is, believe in me: he shall live for ever - In other words, he that believeth to the end shall be saved. My flesh which I will give you - This whole discourse concerning his flesh and blood refers directly to his passion, and but remotely, if at all, to the Lord's Supper.