Daniel says he breaks the covenant "in the
midst of the week" (Daniel 9:27). This puts
his betrayal half way through the Tribulation.

Breaking the covenant and becoming an enemy
of Israel. Paul says: ". . .that day shall not come,
except there come the falling away first, and that
man of sin be revealed, the son of perdition, who
opposeth and exalteth himself above all that is
called God, or that is worshiped, so that he, as
God, sitteth in the temple of God, showing him
self that he is God," 2 Thessalonians 2:3-4