All scripture is inspired of God. He may use whatever means he may to inspire men to do good and to testify of His divinity. He used his son Jesus the Christ, the apostles and prophets. He will even let Satan use the power he has been given to warn man of the impending danger of using evil as a means of doing so called good.
He testifies of His divinity by using the simple things in life, things that people will understand and apply in their lives. All scripture is of God is so far as Gods word has been translated correctly.