John 13:36

Simon Peter said unto him
One might have expected that Peter would have taken some notice of what Christ said last, about love to one another; but he passes over it, and takes no manner of notice of it; which did not arise from inattention to it, or from any dislike of it, or disaffection to it; for it appears from his whole conduct and writings, that he had the utmost regard for it; he very frequently presses it, and most fervently practised it; but having observed some words which dropped from Christ's lips, "whither I go ye cannot come", ( John 13:33 ) ; his mind was intent upon them, was uneasy about them, and very much wanted to know the meaning of them; and as soon as Christ had done speaking, took the opportunity to put the question:

Lord, whither goest thou?
imagining he was going to some distant place in the country, and which was difficult of access; whereby he betrayed his weakness and ignorance, as the Jews did, ( John 6:25 ) .

Jesus answered him, whither I go thou canst not follow me now;
which words imply, that Christ was going somewhere in a little time; he was going to the garden to surrender himself up into the hands of his enemies, and hither Peter could, and did follow him, and therefore is not here meant; he was going to die for his people, in order to take away the sting of death and the curse of the law, and work out salvation for them; he was going to his Father in heaven, to receive gifts for men, and to send the Comforter; to open the way to heaven, take possession of it, and prepare it for his saints; to plead the cause, and transact the business of his dear children; and to receive a kingdom for himself, and return: now hither, as yet, Peter could not follow him; for his time of suffering death was not yet come; Christ had some other work for him to do first; he must open the door of faith to the Gentiles, and preach the Gospel to them:

but thou shall follow me afterwards;
when thy time is come, and thou hast done the work allotted for thee, thou shalt follow me by dying for me; and thou shall follow me into my kingdom and glory, and be for ever with me: all the saints shall follow Christ to heaven, who is their forerunner for them entered; and as sure as he is there, so sure shall they be also; the counsels of God are unalterable, the covenant of grace is firm and sure, the blood of Christ can never be spilled in vain, his prayers and preparations cannot be fruitless, nor the work of the Spirit be ever lost; wherefore not one of those who are given to Christ, and come to him, and follow him here, but shall follow him hereafter.