It is clear from the Bible that words are significant to God's way of doing things.

From the beginning, creation was achieved through the Word, the speech of God represented by Jesus.

In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things came into being through him, and without him not one thing came into being. What has come into being in him was life, and the life was the light of all people.
(John 1.1-4)

In the Old Testament, God's word was often spoken through the prophets, and once spoken, achieved that for which it was intended.

So shall my word be that goes out from my mouth;
  it shall not return to me empty,
but it shall accomplish that which I purpose,
  and succeed in the thing for which I sent it. (Isaiah 55.11)

Jesus continued the tradition of speaking words that would stand for eternity, accomplishing their purpose through or in spite of the frailty of humans.

Heaven and earth will pass away, but my words will not pass away. (Matthew 24.35)

So it is that we have the collected words of God, useful for every purpose of shaping us:

All scripture is inspired by God and is useful for teaching, for reproof, for correction, and for training in righteousness, so that everyone who belongs to God may be proficient, equipped for every good work. (2 Timothy 3.16-17)

Even from this limited and scattered collection of verses we can see how important words are in the formation of God's renewed people. Further, the Spirit uses God's spoken word to continue the ongoing work of inner transformation:

But the Advocate, the Holy Spirit, whom the Father will send in my name, will teach you everything, and remind you of all that I have said to you. (John 14.26)

Our reading is important in defining our beliefs and values, guiding our thinking, modifying our behaviour, shaping our spirit response, guarding our heart.

As I look at my bookshelf I am conscious of the authors who were instrumental in helping me form my spiritual world view: John Stott, David Watson, John White, FF Bruce and Josh McDowell. Then there were the reference books given to me to help give structure and rigour: the New Bible Commentary and Dictionary, and Young's Concordance.

I know of someone who begins a mentoring session with the question: What are you reading? It's the same as asking: what ideas are you excited about? Who is shaping your thinking? I am sure that in the future it may be blogs and websites, or podcasts of sermons that may fulfil the same purpose: the transmission of words to help form character.

And all this is done within the definitive context of the Words that will not pass away, the Bible; the means of testing and sorting all the other words we read. This process of testing is not just the Christian books we read, but the newspapers, the novels and interest books, the articles and magazines, the blogs and websites. God can shape us through many varied words and ways.