Matthew 7:7-11 Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened to you:  For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened.  Or what man is there of you, whom if his son ask bread, will he give him a stone?  Or if he ask a fish, will he give him a serpent?   If ye then, being evil, know how to give good gifts to your children, how much more shall your Father which is in heaven give good things to them that ask him?

People worry that they may receive a stone (the natural mind) from God when they ask for the Holy Spirit.  Others worry that God may give them a serpent (a devil) when they ask for the Holy Spirit.  That is foolish.  These same people usually end up turning to their own natural minds and their own power for their spiritual lives and end up in fleshly religion rather than moving with the Spirit of God.  They were afraid to seek God, but not afraid to follow after their own understanding.  It should have been the other way around.  Sometimes, they become pastors or start preaching on the radio or TV.  What a shame.

See also, Luke 11:9