Quran as a guide
"That is the (holy) book, where there is no doubt. it is a guidance for the cautious (of evil and hell)." (2:2)
"Who believe in the Unseen, are steadfast in prayer, and spend out of what We have provided for them." (2:3)
Source:The Holy Quran ( The Cow, verse 2-3_
Other links:
Why does the Noble Quran use words that have multiple meanings?
How does the Quran present God?