Being poor in spirit means being aware of our spiritual poverty. Being poor in spirit also means being conscious of our constant dependence on God.
Children depend upon their parents for protection and care. Because of that relationship, children are not poor; but if it weren't for their relationship with their parents, they would be helpless and poor indeed. Dependent children spend little time worrying about meals, clothing, and shelter. They assume and they have a right to that all will be provided by their parents. When we come to Christ, we become children of God, and we can trust that our Heavenly Father to provide for us.
You are all children of God through faith in Christ Jesus - Galatians 3:26 .