Albert Barnes Commentary Luke 21:36

"But watch ye at every season, making supplication, that ye may prevail to escape all these things that shall come to pass, and to stand before the Son of man." — Luke 21:36 (ASV)

To stand before the Son of man. These approaching calamities are represented as the coming of the Son of man to judge Jerusalem for its crimes. Its inhabitants were so wicked that they were not worthy to stand before him and would be condemned, and the city would be overthrown. To stand before him here denotes approval, acquittal, favor, and is equivalent to saying that they would be free from these calamities, while they should come upon others. (Romans 14:4; Psalms 1:5; Psalms 130:3; Revelation 6:17).

Perhaps, also, there is a reference here to the day of judgment. See Barnes on Matthew 24:1 and following.