Answer:
Twilight (book 1)
'But of the tree of knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die' Genesis 2:17
New Moon (Book 2)
'These violent delights have violent ends And in their triumph die, like fire and powder Which, as they kiss, consume' Romeo and Juliet, Act II, Scene VI
Eclipse (Book 3)
'Some say the world will end in fire, some say in ice. From what I've tasted of desire, I hold with those who favour fire, But if it had to perish twice, I think I knew enough of hate to say that for destruction ice is also great and would suffice' Robert Frost
Breaking Dawn (Book 4) has several quotes...
'Childhood is not from birth to a certain age and at a certain age The child is grown, and puts away childish things. Childhood is the kingdom where nobody dies.' Edna St. Vincent Millay
'And yet, to say the truth, reason and love keep little company together nowadays' William Shakespeare, A Midsummer Night's Dream, Act III, Scene i
'Personal affection is a luxury you can have only after all your enemies are eliminated. Until then, everyone you love is a hostage, sapping your courage and corrupting your judgment.' Orson Scott Card, Empire