John Chrysostom

As they then were laboring and wearied, Jesus presenteth Himself before them, and doth not at once reveal Himself, so that they enter into converse with Him.

Homily on the Gospel of John 87 ↗

Theophylact of Ohrid

Having appeared to them while they were laboring and exhausted, He does not immediately reveal Himself, but first wishes to enter into conversation with them.

Commentary on John ↗

Gregory the Dialogist

It may be asked, why after His resurrection He stood on the shore to receive the disciples, whereas before He walked on the sea? The sea signifies the world, which is tossed about with various causes of tumults, and the waves of this corruptible life; the shore by its solidity figures the rest eternal. The disciples then, inasmuch as they were still upon the waves of this mortal life, were labouring on the sea; but the Redeemer having by His resurrection thrown off the corruption of the flesh, stood upon the shore.

Catena Aurea by Aquinas ↗

Thomas Aquinas

Now we see the way and stages in which Jesus appeared: first, he allows himself to be seen; secondly he is recognized; and thirdly, he eats with the disciples. The Evangelist says that the day was breaking, it was morning. In the mystical interpretation, morning or the break of day indicates the glory of the resurrection: "Weeping may tarry for the night, but joy comes with the morning" (Ps 30:5); "In the morning I will stand before you, and will see you" (Ps 5:5). …

Commentary on John ↗

Bonaventure

It is asked concerning what it says: Jesus stood on the shore: Gregory asks, since the Lord "before his passion walked upon the waves of the sea in the sight of his disciples, above in chapter 6: what is it that after his resurrection he stood on the shore while his disciples labored on the sea"? Gregory responds: "By the sea the present age is signified, by the solidity of the shore the perpetuity of eternal rest. …

Commentary on John, Chapter 21 ↗