The word of God--the Bible--is an amazing thing. God has spoken through prophets, through poets, and through the pens of the people who wrote the Old and New Testaments by divine inspiration.
This is often difficult to prove from deductive arguments. If someone assumes that Scripture is not the word of God and thus not authoritative, then citing passages within Scripture that affirm the reliability, authority, and inspiration of Scripture is likely to have no effect.
But, the word of God is infused with life through the Holy Spirit. As the author of Hebrews writes in Hebrews 4:12:
For the word of God is living and active, sharper than any two-edged sword, piercing to the division of soul and of spirit, of joints and of marrow, and discerning the thoughts and intentions of the heart.
In Isaiah 55:10-11 we have been told that God's word will have an impact on this world, and that it will accomplish God's purpose on the earth:
For as the rain and the snow come down from heaven
and do not return there but water the earth,
making it bring forth and sprout,
giving seed to the sower and bread to the eater,
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 shall succeed in the thing for which I sent it.
Of course, none of these verses mean much to someone who already doesn't believe, but for those of us who have, by God's grace, gained an understanding of his faithfulness they are encouraging. For those of us who have felt the light of God's love shining down on us like beams of sun through the clouds, we expect to see God's word do mighty works in us and around us.
The video below will take only a few minutes to watch, but it is worth your time.
The video is an account of how a seemingly chance interaction with Scripture led to salvation. The Holy Spirit works through his inspired word to bring about redemption even in the most unlikely circumstances.