Voice of evil
The final voice we hear is the voice of evil. We are all quite familiar with temptations. They are most often appealing to the flesh, our pride, or our vanity. They try to get us to go contrary to righteous promptings.
I believe that the evil ones, while not able to hear our thoughts, are keenly aware of when we are receiving promptings from righteous spiritual sources. I believe it because when there is a prompting to do good, the evil ones immediately rant against it, railing with many reasons why we should do otherwise.
As well, the evil ones certainly know the behaviors and weaknesses of mankind. and eventually they com to know and recognize us. They have millennia of experience in discerning the mood, emotions and likely intentions of their human prey. My experiences have led me to believe that these beings are hateful and angry and have very real intent to destroy us. What seems like a vague scuffle to us is an all-out war to them, and they fully intend to win. Their goal is to get us to obey them, thus separating us from the voice of the Holy Spirit.
An example of these three voices operating in our lives probably happened to a lot of us just last Fast Sunday. The voice of the Holy Spirit might have prompted you to bear your testimony. The opposition, keenly aware of what is going on and knowing you and your weakness, would immediately counter with a barrage of clever arguments tailor-made for you: "You won't know what to say. It will be embarrassing. You will just start crying. Leave the time for other people. Nobedy really cares about what you think anyway, " and similar lies. Your mind then says, "oh, my goodness what should I do?"
When we are able to identify these three voices correctly, then we don't need to ask ourselves what we "should" do, because we"should" bear our testimony. This is what Christ desires of us at that moment. The real question is, "Will I be obedient and bear my testimony?"