Ambassadors go to foreign countries on a mission for their nations. Missionaries go to many countries on a mission for Jesus Christ through His Church. Every Christian goes on a mission each day for his or her Lord and Savior Jesus Christ.
Mission defines and determines our lives.
He tells us in today's key verse. Herod was trying to arrest Jesus. Herod would have interfered with Jesus' mission had her succeeded. We really don't know the motives of the Pharisees telling Jesus to depart. We certainly can surmise their motive.