Rabmag is a Babylonian title–chief or head of the magi, or wise men.
Jeremiah 39:13 (NKJV)
So Nebuzaradan the captain of the guard sent Nebushasban, Rabsaris, Nergal-Sharezer, Rabmag, and all the king of Babylon’s chief officers;
After Daniel interpreted the king’s dreams, Nebuchadnezzar promoted Daniel.
Daniel 2:48 (NKJV)
Then the king promoted Daniel and gave him many great gifts; and he made him ruler over the whole province of Babylon, and chief administrator over all the wise men of Babylon.
The ancient Chaldeans studied the heavens. Daniel, as the Rabmag, most likely taught his students of the heavens about the coming King of the Jews.
Numbers 24:17-19 (NKJV)
“I see Him, but not now;
I behold Him, but not near;
A Star shall come out of Jacob;
A Scepter shall rise out of Israel . . .
While Israel does valiantly.
Out of Jacob One shall have dominion . . .”
We thank You, Father, for the star that shone on the stable in Bethlehem, for the spiritual authority of Christ Jesus, and for the establishment of His kingdom on earth. Amen.