"Believe me, love, it was the nightingale."(3.5.5)
Romeo and Juliet are in Juliet's Room
"It was the lark, the herald of the morn, No nightingale." (3.5.6-7)
Romeo and Juliet are trying to determine what kind of bird is singing outside, a lark or an nightingale.
"Night's candles are burnt out, and jocund day." (3.4.9)
Juliet believe that the nightingale is the type of bird that is singing outside her room. The Nightingale is the bird that sings in the dark or the night--meaning that since it is still nighttime, Romeo does not have to leave Juliet just yet. Their love must remain in secret.
Act 3 Scene 5
"Your lady mother is coming to your chamber" (3.5.39)
Romeo denies what Juliet said about it being the nightingale that is outside signing. Instead he believes that it is the lark, it will soon be time for Romeo to leave Juliet so he doesn't end up getting caught. He must go against daylight and the light.
Romeo (leaving), Juliet and Nurse in Juliet's room
"Then, window, let day in, and let life out." (3.5.41)
This is another descriptive quote of Romeo saying and describing that the night has truly gone and hu must actually leave. Referring to the 'Night's candles being burnt out'; it means that night is not present any more and instead day is here.
Lady Capulet is coming up the stairs to greet her daughter and Romeo is in a frenzy to leave so he won't get caught.
The nurse is aware of the secret relationship between the two lovers, Romeo and Juliet. She helps the two out by warning them very urgently that Lady Capulet is coming up the stairs. Romeo now must leave and be gone, pretend that he was never even with Juliet. Although their love very deep, they can't let it be discovered.
"The day is broke; be wary; look about." (3.5.40)
Even though both Juliet and Romeo do not want to leave one another, they have no choice. Their secret love can't be revelaed, especially if it's by Lady Capulet who hates Romeo ever so much. Juliet claims to let the daylight in but let her life out, which is referring to Romeo. Juliet quoting that her life is Romeo is a true sign of the passionate love that he two lovers share.
Sad to not be with Juliet, Romeo asks for a kiss before he has to part from Juliet. This also portrays the passionate love that they share but also portrays the mystery and secret that is needed to keep this love existing. Romeo and Juliet can't let others know that the two are in deep love.
"Farewell, farewell. One kiss and I'll decend." (3.5.42)