I have a friend who is constantly hearing 'voices' that pertain to blasphemy, and they are beginning to wonder if they are prompted by Satan. How can I comfort my friend? They are worried that these 'thoughts' are going to send them to hell. I keep telling them that it is just a trial, but it becomes harder and harder every day to withstand these things.     

        We must understand we do not have control over what enters our minds, especially when we dream. It is how we react to them that is the key issue. However, your conscience can react to the things that you are exposed to during your normal daily life, which is why it is important to keep clear and Godly thoughts. I do not believe Satan can enter our minds, or place thoughts in them. Yes, he can expose evil things to you to 'tempt' you but it's your free will as to how you respond. I get 'wrong' thoughts in my mind too, as we all do. When it happens, I immediately dismiss them by thinking of Jesus, say maybe a scene I saw in a movie when He was walking and teaching people. I ask for forgiveness and help in 'taking away' these evil thoughts, as it says in the Lord's prayer in Mathew 6:13;

                                                   "And lead us not into temptation, but deliver us from evil......"

        No, I do not believe, that in ones honest searching for our Lord, when these things happen it will 'send him/her to hell'. As one of the prayers in Psalms 116:8 says;

                                "For thou hast delivered my soul from death, mine eyes from tears, and my feet from  falling."

and in Psalms 119:113;
                                                             "I hate vain thoughts: but thy law do I love."

and lastly in Psalms 34:4;

                                            "I sought the LORD, and he heard me, and delivered me from all my fears."

        Be careful about saying this persons situation is a 'trial'. Could it be? Yes, but neither you nor I have the ability to say for sure. In the story of Job on this site, I point out, when Job's friends were telling Job what they thought God was thinking or doing, what God's response was. You can view this under the link of the home page 'Biblical Study Topics' then 'Understanding God'. I would suggest, you tell your friend in a loving way to pray and ask for guidance. Prayer for a problem like this is what God wants and commands us to do, and then tell them to remember;

"Be still, and know that I am God: I will be exalted among the heathen, I will be exalted  in the earth." Psalms 46:10