John Calvin Commentary John 21:12

"Jesus saith unto them, Come [and] break your fast. And none of the disciples durst inquire of him, Who art thou? knowing that it was the Lord." — John 21:12 (ASV)

And not one of his disciples dared to ask him. It might be asked, what prevented them? Was it shame arising from reverence, or was it something else? But if Christ saw that they were in a state of uncertainty, he should have removed their doubt, as he had done on many other occasions. I reply, there was no other reason for shame, except that they were not sufficiently certain that he was the Christ; for it is not usual for us to inquire about matters that are doubtful and obscure. The Evangelist, therefore, means that the disciples did not ask Christ because they were afraid of offending him; so plain and manifest were the signs by which he had made himself known to them.