Psalm 23:1. The 23rd Psalm say, "The Lord is our shepherd. We shall not want." If this is true, why do we lack? The reason we lack is that we do not really believe God's promises and we are not obedient to Him. God's promises are offered to all that accept Jesus Christ as their Lord and Savior. If we truly believe in God's promises, we will lack no good thing.
Psalm 23:1. Psalm 23 teaches us that we have a good shepherd that will take care of all of our needs. If God is our Shepherd, then we are His sheep. As a good sheep we rely on God for all of our needs. If we do not stay close to God or listen to Him, we will go astray and go lacking. A sheep with the Lord as it's shepherd is powerful and can take on any challenge of this world.