Tehillim 149:1:
הללויה, שירו להשם שיר חדש, תהלתו בקהל חסידים.
Halleluya, sing to God a new song, his praise among Chassidim.
Rabbi Naftali of Ropshitz explained homiletically: A new song must be found for God because all the old praises have been appropriated by Chassidim for their Rebbes…