Though the Lord had brought them out of Egypt, the people began grumbling against God because they were hungry and thirsty. Despite their complaining, the Lord graciously provided for them. Instead of striking them for their sin, God instructed Moses to strike a rock to bring forth water. In the same way, living water flows from the pierced side of Christ when He is lifted up on the cross for the sins of the world. He is the well from which the Holy Spirit is poured out and becomes in His people “a spring of water welling up to eternal life.”
