The Lord thunders at the head of his army; his forces are beyond number, and mighty are those who obey his command (Joel 2:11a NIV).
Our God is powerful. He can command with a force like that of thunder. His forces are numberless. So we have here a picture of tremendous power: God full of majesty and power; commanding with absolute authority, and obeyed by forces that cannot be counted!
In addition to these, we have, here described for us the quality of those who obey God’s command: they are mighty. It is very important to note that God is not basically calling mighty people and asking them to do some task for Him. He calls people and then asks them to do something. God doesn’t ask whether the chosen person is mighty or not! What God desires is obedience.
And when a person obeys His command He becomes mighty. This is not a popular concept in this world. In the world, we find mighty men in armies. They are there because they are strong. But God tells us that it does not matter whether you are naturally strong or not. What matters is obedience. It is in the doing of the task which God has given you that you become mighty.
So it is God who gives strength to do the task. It is imparted to those who obey His command. Thus they become mighty. Quite often we wait to be made strong. We think that after becoming mighty we will do some valiant thing for God. This is a fatal mistake. You never become mighty except by obedience to God’s command. Might is not something that we gain to qualify us for God’s service; but we become mighty by obeying!