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.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: xiii. de Civ. Dei, c. xxii