What Does it Mean that “I Shall Not Want”?
Psalm 23 does not say I shall not need. Jesus makes it clear that God is going to provide for all our physical needs and we shouldn't even worry about that. Psalm 23,  says I shall not want, speaking to our desires. God can also fulfill me. He can satisfy my heart. So when David says “I shall not want” he's say ing two things:  One, there are areas in my life that only God can fulfill and He will fulfill them. Two, I've made the decision not to desire anything outside of the scope of what God wants for me. In this shepherd-sheep relationship with God, I am satisfied.