And in that day there shall be a root of Jesse, which shall stand for an ensign of the people; to it shall the Gentiles seek: and his rest shall be glorious. —ISAIAH 11:10
[Christ] is a military flag or ensign—a banner of war. This teaches us that Christianity is a warfare, and that Christ and Christians are warriors. But who are the enemies, and what is the quarrel? The enemies are the devil and the world and the flesh. The cause we are in is the glory of God.
It is by the flag that belongs to the company, as much as by anything, that all the soldiers in that company, being gathered together, are knit together into one. That is their center of unity—not only their having but one captain and being engaged in one cause and their taking one and the same oath, but having the same flag. So our great center of unity is our Lord Jesus Christ, not only as our one captain, but as our ensign.
The great work of ministers is to lift up Christ to people, to set Him forth as the most eligible and desirable, both on the account of what He is in Himself, and what He is to poor sinners. They are the friends of the bridegroom, wooing for Him, not for themselves.
Now here is an ensign that lives forever, a flag that cannot be taken. He always has been, is, and will be Jesus the conqueror.