God cannot tell a lie. Satan cannot tell the truth.

But, you do both.

Hebrews 6:18 (KJV) – that by two immutable things, in which it was impossible for God to lie, we might have a strong consolation, who have fled for refuge to lay hold upon the hope set before us.

John 8:44 (KJV) – ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it.