Words are the tools, the weapons in our arsenal, if you will. God uses them and so does satan. If satan (or one of his emmisary's) is in you, he speaks to your spirit directly, if he is outside of you he uses people or demons to speak to you. It's up to you to believe him or not. He used words to tempt Eve and he's been doing the same ever since.
Words are so powerful. By them God created all that exists (except us, he used his hands to create us). By them, satan destroys all God holds dear and by them we can all be restored to right standing with God. Really, these words I'm writing now and every word I'll speak or write from womb to tomb is Eternal, that is, known by God in Eternity. This is pre-destination. God simply knows you, intimately knows you, whether you know him or not.
Do not recieve with your heart anything satan says. How can you discern satan's voice from God's? By reading and ingesting God's words written in the Bible. They are a small, small portion of all he's spoken but think about this - out of all he's ever spoken or thought, they are the ones he chose to write down for us, so how important must they be for us? Extremely! By them we learn what his words sound like and what his will is. How he thinks and feels about every subject imaginable.
So when satan speaks, disguised as an angel of light, we know it is him, not Jesus because it doesn't line up with God's written words. If a thought tries to get you to question God's word to you "Has God said?" "You shall not surely die", then you know it's author, don't you? I am only saying never question what the Holy Spirit has taught you, not what you've been taught in Church, by the way.
Crucify the words of satan in you while letting the words of God ressurect your soul unto everlasting life. What came to Abraham? The Word of the Lord.