In Zechariah 11, the Shepherd uses two staffs: Favor (representing God's covenantal protection) and Union (representing the brotherhood of Israel). When the Shepherd is rejected, he breaks both staffs. This is an apocalyptic act representing the annulment of the Mosaic system.
The breaking of the first staff, Favor, signified that God would no longer restrain the nations from destroying Israel. The breaking of Union signified the horrific civil war that erupted within Jerusalem during the Roman siege. By AD 70, the old world had been snapped in two. The Old Covenant "vanished away" (Hebrews 8:13), leaving the New Covenant as the only valid administration between God and man.