God's choosing and leading Israel is valuable history. "These things happened to them as examples and were written down as warnings for us, on whom the fulfillment of the ages has come" (1Co 10:11). Old Testament content is meaningful to Christians even though "Jesus has become the guarantee of a better covenant" (Heb 7:22). Are we permitted then to copy-and-paste only what we feel applies from the Old Testament to the New Testament? You can only be selective if the New Testament states that something has been superceded. We must realize that "I the Lord do not change" (Mal 3:6). "Jesus Christ is the same yesterday and today and forever" (Heb 13:8). Therefore, his desire to heal continues.
The Psalms confirm this. The Lord "forgives your sins and heals all your diseases" (Ps 103:3). Some ills are your own fault. They "became fools . . . and suffered affliction" (107:17). Then they called for help and "he sent forth his word and healed them" (:20). Was this physical or spiritual? It was partly the former since they "loathed all food and drew near the gates of death" (:18). Is it strange that God's word was involved in the healing? Not scripturally. God's words are "life to those who find them and health to a man's whole body" (Pr 4:22). If you follow the instructions you can be healed. Then you must profess the advice because "the tongue of the wise brings healing" (12:18). "The tongue has the power of life and death, and those who love it will eat its fruit" (8:21).