Dan Brown's 2000 thriller Angels and Demons introduced the character of Robert Langdon, also featured in his worldwide bestseller The Da Vinci Code.

A good place for quotes is Wikiquotes, which has a page that mixes quotes from the novel itself and from the film of the same name. The link below from shepherdproject.com also has quotes separated by theme.

Here are some quotes from the novel:

Since the beginning of time, spirituality and religion have been called on to fill in the gaps that science did not understand. The rising and setting of the sun was once attributed to Helios and a flaming chariot. Earthquakes and tidal waves were the wrath of Poseidon. Science has now proven those gods to be false idols. Soon all gods will be proven to be false idols. Science has now provided answers to almost every question man can ask.

• This quote argues for the importance of science not to explicitly disprove religion but to provide better answers to real problems and issues.

Faith is universal. Our specific methods for understanding it are arbitrary. Some of us pray to Jesus, some us go to Mecca, some of us study subatomic particles. In the end we are all just searching for truth, that which is greater than ourselves.

• This quote explains how individuals search for meaning in life through different methods; science provides meaning in one way, while religious faith provides it in another.

Robert Langdon: I’m academic. My mind tells me I will never understand God.
Camerlengo: And your heart?
Robert Langdon: Tells me I am not meant to. Faith is a gift that i am yet to receive.

• This quote shows how Robert Langdon honestly equates his lack of faith to agnosticism instead of atheism, since he accepts that "he will never understand God," and that faith comes a non-rational place.

There are any number of good quotes from the novel; check Google Books to see others directly from the text.

(Quotes: Brown, Angels and Demons, en.wikiquote.org)