How does the story of Moses and the rock demonstrate God's grace?

When the people of Israel complained for water, Moses struck the rock, representing the law's condemnation. God's command was for Moses to speak to the rock, symbolizing that grace had already been provided through Christ. The striking of the rock twice showed a misunderstanding of God's redemptive plan; the law cannot strike the innocent. Instead, Christ, the rock, was smitten once for our sins. Through this act, God illustrates His grace, showing that salvation and eternal life come only through faith in Him, not the works of the law.