John 13:36
“Simon Peter said unto Him, Lord, where are you going? Jesus answered him, Whither I go you can not follow Me now, but you shall follow Me afterwards.”
1. A great thing is love, and stronger than fire itself, and it goes up to the very heaven; there is no hindrance which can restrain its tearing force. And so the most fervent Peter, when he hears, “Whither I go ye cannot come,” what says he? “Lord, where are you going?” and this he said, not so much from wish to learn, as from desire to follow. To say openly, “I go,” he dared not yet, but, “Where are you going?” Christ answered, not to his words, but to his thoughts. For that this was his wish, is clear from what Christ said, “Whither I go you can not follow Me now.” Do you see that he longed for the following Him, and therefore asked the question? And when he heard, “you shall follow Me afterwards,” not even so did he restrain his longing, and, though he had gained good hopes, he is so eager as to say,
Source: Homilies on the Gospel of John (New Advent)