God needs your help to expand his Kingdom, but you must realize that without you He can use someone else. God always blesses anyone who supports his work. Luke 10 reveals that there is a great harvest of souls who can be led to salvation but God needs you and I to partner with him to win souls, preach the Gospel.
God has got power over all diseases and would like to heal people but he needs you and I to make ourselves available so He can fill us with His spirit and enable us to be vessels for healing.