Adam Clarke on Daniel 11:33

And they that understand - The apostles and primitive Christians in general, who understood from the prophets, and his own actions, that Jesus was the true Messiah.

Instruct many - Preach the Gospel every where, and convert multitudes to the faith.

Yet they shall fall by the sword, and by flame, by captivity, and by spoil, many days - They were exposed to the malice and fury of their enemies, during Ten State Persecutions, and suffered all kinds of tortures, with but little intermission, for three hundred years. - Newton.