1Sa_16:14 But the Spirit of the LORD departed from Saul, and an evil spirit from the LORD troubled him. The life that the Holy Spirit rules, there's no room for the Devil or his demons. 1Th_5:19 Quench not the Spirit. A Spirit-filled life is a life on fire for God. Quenching the Spirit is a process. If we continue in sin ("Grieve NOT the Holy Spirit"), shutting our ears to what the Spirit have to say...,hardening our hearts, being rebellious, the fire of the Holy Spirit will gradually fade until its gone. Our sin is like water on a fire. So do our sin quench the Spirit. 1Sa_16:23 And it came to pass, when the evil spirit from God was upon Saul, that David took an harp, and played with his hand: so Saul was refreshed, and was well, and the evil spirit departed from him. Where the presence of the Lord is, demons cannot stand. Saul's problem was that the empty space that the evil spirit left was not refilled by the Spirit Holy. 1Sa_18:10 And it came to pass on the morrow, that the evil spirit from God came upon Saul, and he prophesied in the midst of the house: and David played with his hand, as at other times: and there was a javelin in Saul's hand, beware of church folks who under praise and worship prophecy, speak in tongues with a javelin of hate, murder, envy in the right hand of the soul, mind. You might want to make sure by what spirit they prophecy, speak in tongues etc.