It was only by faith in Christ that they could secure pardon of sin and receive strength to obey God's law. They must cease to rely upon their own efforts for salvation, they must trust wholly in the merits of the promised Saviour, if they would be accepted of God.
The fatal effects of sin can be removed only by the provision that God has made. The Israelites saved their lives by looking upon the uplifted serpent. That look implied faith. They lived because they believed God's word, and trusted in the means provided for their recover. So to sinner may look to Christ, and live. He receives pardon through faith in the atoning sacrifice. Unlike the inert and lifeless symbol, Christ has power and virtue in Himself to heal the repenting sinner.