Case in point: The Devil took Him to Jerusalem, to the highest point of the Temple and said, "If you are the Son of God, jump off! For the scriptures say, 'He orders His angels to protect you. And they will hold you with their hands to keep you from striking your foot on a stone.'" Jesus responded, "The Scriptures also state, 'Do not put the Lord your God to the test.'" Matthew 4:5-7 or Luke 4:9-12.
There is no actual verse that states Satan knows scripture, although from the above demonstrates he is very well acquainted and versed, and will twist the Word to lead many astray. However, the key is to understand, based on the above, that Lucifer masquerades himself as an angel of light (2 Corinthians 11:14), and that you should always test the spirits to see whether they (or the message) are from God (1 John 4:1-3).
Now, back on topic. What exactly were we talking about?
Kevin