John 21:12

What then doth Jesus? "Come," He saith, "dine." "And none of them durst ask Him." For they no longer had the same boldness, nor were they so confident, nor did they now approach Him with speech, but with silence and great fear and reverence, sat down giving heed to Him. "For they knew that it was the Lord." And therefore they did not ask Him, "Who art Thou?" But seeing that His form was altered, and full of much awfulness, they were greatly amazed, and desired to ask somewhat concerning it; but fear, and their knowledge that He was not some other, but the Same, checked the enquiry, and they only ate what He created for them with a greater exertion of power than before. For here He no more looketh to heaven, nor performeth those human acts, showing that those also which He did were done by way of condescension.

The bodies of the righteous at the resurrection will need neither any fruit to preserve them from dying of disease or the wasting decay of old age nor any bodily nourishment to prevent hunger and thirst. For they will be endowed with such a sure and inviolable gift of immortality that they will not eat because they have to, but only if they want to. Not the power but the necessity of eating and drinking shall be taken away from them … just like our Savior after his resurrection took meat and drink with his disciples, with spiritual but still real flesh, not for the sake of nourishment, but in an exercise of his power.

(Tract. cxxiii) The fishing being over, our Lord invites them to dine: Jesus saith unto them, Come and dine. (xiii. de Civ. Dei, c. xxii) The bodies of the just, when they rise again, shall need neither the word of life that they die not of disease, or old age, nor any bodily nourishment to prevent hunger and thirst. For they shall be endowed with a sure and inviolable gift of immortality, that they shall not eat of necessity, but only be able to eat if they will. Not the power, but the need of eating and drinking shall be taken away from them; in like manner as our Saviour after His resurrection took meat and drink with His disciples, with spiritual but still real flesh, not for the sake of nourishment, but in exercise of a power. And none of His disciples durst ask Him, who art Thou? knowing that it was the Lord. (Tract. cxxii) No one dared to doubt that it was He, much less deny it; so evident was it. Had any one doubted, he would have asked.

When the fishing was over, "Jesus saith unto them, Come [and] dine. And none of those who sat down dared to ask Him, Who art Thou? knowing that it was the Lord." If, then, they knew, what need was there to ask? and if there was no need wherefore is it said, "they dared not," as if there were need, but, from some fear or other, they dared not? The meaning here, therefore, is: so great was the evidence of the truth that Jesus Himself had appeared to these disciples, that not one of them dared not merely to deny, but even to doubt it; for had any of them doubted it, he ought certainly to have asked. In this sense, therefore, it was said, "No one dared to ask Him, Who art Thou?" as if it were, No one dared to doubt that it was He Himself.

(Hom. xxiv.) By holding this last feast with seven disciples, he declares that they only who are full of the sevenfold grace of the Holy Spirit, shall be with Him in the eternal feast. Time also is reckoned by periods of seven days, and perfection is often designated by the number seven. They therefore feast upon the presence of the Truth in that last banquet, who now strive for perfection.