The greatest part of what is said here, was said by our Saviour before, 1 Thessalonians 7:34; (see the explication of it there); only here, instead of ye shall not find me, is, ye shall die in your sins; a phrase we shall find in Ezekiel 3:18,19, which doubtless signifieth, in the guilt of your sins, not removed from you; and is a threatening of eternal death, as well as temporal in the destruction of Jerusalem: and those who do so, cannot come into heaven, where Christ is.
Related Commentaries of John 8:21
John 8:21
21 Then said Jesus again unto them,I go my way, and ye shall seek me, and shall die in your sins: whither I go, ye cannot come.