Which lines in this excerpt from shakespeare's romeo and juliet foreshadow the tragic ending of the play?

Romeo saying,

"I fear, too early: for my mind misgives

Some consequence yet hanging in the stars

Shall bitterly begin his fearful date

With this night's revels and expire the term

Of a despised life closed in my bre-ast

By some vi-le forfeit of untimely death.

But He, that hath the steerage of my course,

Direct my sail! On, lus-ty gentlemen."

Explanation:

Foreshadowing in literature is an element that is used by the writer to give signs of the events that are going to take place.

From the beginning of the play, the tragic fa-te of the lover's and tra-gic ending of the play was foreshadowed. The de-ath of the lovers was foreshadowed in the Pro-lo-gue of the play.  

The tragic ending of the play was foreshadowed in the conversation of Romeo with his friend Ben-volio in Act 1, Scene 4, as stated above.