The Still Waters of Rest

David is not referring to the physical aspect of water. He is speaking about spiritual water for the soul. "Still waters" refers to the Word of God by the Spirit of God through the life of God.
God leads us to His peace. He does not drive or force us. Rather, He prepares the way; making peace possible. It is up to us to follow His pathway to peace. It is refreshing, peaceful, reassuring and rewarding. Do we spend enough time "drinking" from His still "waters"?