The people well knew that there was no power in the serpent of brass to cause such a change in those who looked upon it. The healing virtue was from God alone. In His wisdom He chose this way of displaying His power. By this simple means the people were made to realize that this affliction had been brought upon them by their sins. They were also assured that while obeying God they had no reason to fear, for He would preserve them.
The lifting up of the brazen serpent was to teach Israel an important lesson. They could not save themselves from the fatal effect of the poison in their wounds. God alone was able to heal them. Yet they were required to show their faith in the provision which He had made. They must look in order to live. It was their faith that was acceptable with God, and by looking upon the serpent their faith was shown. They knew that there was no virtue in the serpent itself, but it was a symbol of Christ; and the necessity of faith in His merits was thus presented to their minds. (Patriarchs and Prophets, 430)
Reflection: The Bible says that faith without works is dead. Our characters can only grow by our trust and faith in Jesus. We, like God's people of old, must look in order to live. In the end it will be our faith through Christ that is acceptable to God.