Albert Barnes Commentary Isaiah 65:14

"behold, my servants shall sing for joy of heart, but ye shall cry for sorrow of heart, and shall wail for vexation of spirit." — Isaiah 65:14 (ASV)

Shall sing for joy of heart — They who serve me shall have abundant occasion of rejoicing. But you shall howl. You shall shriek under the anguish and distress that shall come upon you.

For vexation of spirit — Margin, as in Hebrew, ‘Breaking.’ That is, your spirit shall be broken and crushed under the weight of the calamities that shall come upon you.