What does John 21:12-14 mean?

12 Jesus saith unto them, Come and dine. And none of the disciples durst ask him, Who art thou? knowing that it was the Lord. 13 Jesus then cometh, and taketh bread, and giveth them, and fish likewise. 14 This is now the third time that Jesus shewed himself to his disciples, after that he was risen from the dead. (John 21:12-14 KJV)

William Burkitt’s Commentary

A two-fold reason may be assigned why Christ did at this time invite and call his disciples to dine with him: the first and more principal reason was, to evidence to them the reality of his resurrection, and to assure them of the truth of his manhood, that they might not think it was an apparition only. By the miracle in catching the fishes, he proved himself to be God; by his present eating of the fish, he evidenced himself to be man, and consequently teaches us that our exalted High Priest continues our kinsman in heaven. He is still bone of our bone, and flesh of our flesh; he has taken possession of heaven in our nature, sitting there in our glorified humaninty united to the glorious Deity, clothed with that body which hung in its blood and gore upon the cross, but now shining brighter than ten thousand suns. The second and less principal reason why Christ called his disciples to dine with him, was this, to show his tender care over the bodies of his dear disciples, as being the tabernacles of his own Spirit, the temples of the Holy Ghost; therefore Christ encourages, though not to the pampering, yet to the refreshing of them: Jesus said unto them, Come and dine. And he would not confer with them till they had dined; as the next verse shows.