God's Providence permits Israel to be conquered because of their sins and because God knows the good that He can bring out of this defeat.
Daniel and his companions are without blemish, like the sheep used in sacrifices to God in the Old Testament Law.
Daniel does not want to eat from the king's food, because he would be defiled by eating the food of Gentiles. But he is required to do so, so he trusts in God and proposes a test to see which foods provided the greater health. By God's Providence, he succeeds in convincing the chief of the guard to let them eat foods that would not defile them.
Daniel had wisdom from God, more than all the advisors of the king put together, because he had love and faith and hope. Wisdom does not come from I.Q. or from studying, but from God.
The word magos, in the Latin text, is the same word often translated in the Gospel of Matthew as Magi. In this case, it probably refers not merely to wise men or learned men, but those specializing in interpreting the stars, i.e., astrologers.