Jesus is willing to heal, for when the leper asked, he said "'I am willing, . . . Be clean!'" (Mt 8:3). But you have to be ready to receive. When the blind man said he was ready Jesus replied, "'According to your faith will it be done to you'" (9:29). You have to have faith to believe. "It is with your heart that you believe" (Ro 10:10). "Faith comes from hearing" (:17) so you must have input. But it is with your inner self and not exclusively with your intellect that you believe in spiritual things. "'Everything is possible for him who believes'" (Mk 9:23).
Jesus said, "'Have faith in God'" (Mk 11:22). To believe is having faith. "'If you believe you will receive whatever you ask for in prayer'" (Mt 21:22). "'Therefore all things which you pray and ask, believe that you have received them, and they will be granted you'" (Mk 11:24). Verse 24 beginning with "therefore" is predicated on the preceding one. Jesus explained "'if anyone says to this mountain, 'Go throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him'" (:23). The person commands something to happen and then believes he has already received it. Also he does not doubt it will be done. When Peter "saw the wind, he was afraid and beginning to sink, cried out" (Mt 14:30). Jesus caught him saying, "'You of little faith . . . why did you doubt?'" (:31). Peter had the faith because Jesus said, "'Come'" (:29), but doubt cancelled faith.