Anyone have any thoughts on the bold portion of the following passage (meaning, in v.20)?
Matthew 24:15-21 [re: the middle of the future tribulation period] -
15 Therefore when you shall see ‘the abomination [singular] of desolation,’ having been spoken of by the prophet Daniel [the "singular" is in Dan12:11], standing in the holy place—the one reading, let him understand— 16 then those in Judea, let them flee to the mountains;
[...]
20 But pray that your flight might not be in winter, nor on a Sabbath. 21 For then there will be great tribulation, such as has not been from the beginning of the world until now, and never shall be.