John Calvin Commentary John 8:51

"Verily, verily, I say unto you, If a man keep my word, he shall never see death." — John 8:51 (ASV)

Truly, truly, I say to you. Christ unquestionably knew that some people in that multitude were receptive, and that others of them were not opposed to his doctrine. For this reason, he intended to terrify the wicked whose malice was hopeless, but to do so in such a manner as to leave grounds for consolation for the good, or to draw to himself those who were not yet ruined.

Whatever dislike of the word of God, therefore, may be felt by most people, yet the faithful teacher should not be entirely focused on rebuking the wicked, but should also impart the doctrine of salvation to the children of God, and endeavor to bring them to sound understanding, if there are any among them who are not completely incurable.

In this passage, therefore, Christ promises eternal life to his disciples, but demands disciples who shall not only prick up their ears, like donkeys, or profess with their mouth that they approve of his doctrine, but who shall keep his doctrine as a precious treasure. He says that they shall never see death; for, when faith gives life to a person's soul, death already has its sting extracted and its venom removed, and so cannot inflict a deadly wound.