Where do inner ‘voices’ originate?
Your free will chooses what action to take. It is not God that made the person do it; nor is it Satan that made them do it. It is their free will, the decision having been made after having heard both sides of morality, good and evil. .
He has also written His Laws in our hearts! This truth is found in the Holy Bible, in both, the Old and the New Testament. God said:
“But this shall be the covenant that I will make (…) after those days, says the Lord: I will put my law within them; I will write it in their hearts; I will be their God, and they shall be my people.” [Jeremiah 31:33; Hebrews 8:10 & 10:16]
Not only has God placed His laws in your hearts, He has also made His dwelling within us. “Or do you not know that your body is a temple of the Holy Spirit within you, which you have from God, and that you are not your own? For you were bought with a price; therefore glorify God in your body.” [1 Corinthians 6:19-20]
Therefore, how can we say that we do not know right from wrong? How can we say that God does not speak to us in our hearts? How can we say, “I did not know what I was doing?”
In the Gospel of Mark 4:14-20, the Parable of the Sower explains to us why it is that many do not hear the inner Voice of God that speaks within their hearts.
“The sower (God) sows the word. These are the ones on the path where the word is sown: when they hear, Satan immediately comes and takes away the word that is sown in them. And these are the ones sown on rocky ground: when they hear the word, they immediately receive it with joy. But they have no root, and endure only for a while; then, when trouble or persecution arises on account of the word, immediately they fall away. And others are those sown among the thorns, these are the ones who hear the word but the cares of the world, and the lure of wealth, and the desire for other things come in and choke the word and it yields nothing. And these are the ones sown on the good soil: they hear the word and accept it and bear fruit, thirty and sixty and a hundred-fold.”
Or you can take the bait and pay the price, there are consequences to what we do. For example you remember the first time you committed a mortal sin? You didn’t know how the effects of what you were going to do would effect you, you never did this before, how could you? Just like in Genesis “Is was desirable” But the law was known, and they indeed in free-will made a choice. And they took the bait and paid the price.