What can you kill spirits with?

a prayer...God wants us to trust in him, so if we pray then those bad spirits WILL go away. I went through it, and i wouldn't go to sleep at night cause of those bad spirits, but God wanted me to go through that, cause its a test of his. You wont under stand it until the outcome. Maby God is tryin to tell you something all i can tell you is to listen to his voice. he will say it in your heart and those bad spirits wont go away intil you really put your trust in him