Albert Barnes Commentary Matthew 24:15

"When therefore ye see the abomination of desolation, which was spoken of through Daniel the prophet, standing in the holy place (let him that readeth understand)," — Matthew 24:15 (ASV)

The abomination of desolation. This is a Hebrew expression, meaning an abominable or hateful destroyer. The Gentiles were all held in abomination by the Jews (Acts 10:28). The abomination of desolation means the Roman army, and is so explained by Luke 21:20. The Roman army is further called the abomination on account of the images of the emperor and the eagles, carried in front of the legions, and regarded by the Romans with divine honors.

Spoken of by Daniel the prophet (Daniel 9:26–27; Daniel 11:31; Daniel 12:11).

Stand in the holy place. Mark says, standing where it ought not, meaning the same thing. All Jerusalem was esteemed holy (Matthew 4:5).

The meaning of this is, when you see the Roman armies standing in the holy city, or encamped around the temple, or the Roman ensigns or standards in the temple. Josephus further relates that when the city was taken, the Romans brought their idols into the temple, and placed them over the eastern gate, and sacrificed to them there (Jewish Wars, Book 6, Chapter 6, Section 1).

Whoso readeth, etc. This seems to be a remark made by the evangelist, to direct the attention of the reader particularly to the meaning of the prophecy by Daniel.