NET
21 For then there will be great suffering unlike anything that has happened from the beginning of the world until now, or ever will happen.
Darby
21 for then shall there be great tribulation, such as has not been from [the] beginning of [the] world until now, nor ever shall be;
KJV
21 “For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be.”