Why must the friar rush to Juliet?

Answer 1

After he hears that Friar John has not been able to deliver his message to Romeo, he says "Now must I to the monument alone; Within this three hours will fair Juliet wake: She will beshrew me much that Romeo Hath had no notice of these accidents". However, he should have realized long before that Romeo would have no notice of the fact that Juliet was not dead and would be waking up in an hour because the wedding had been moved up a day. He was officiating at the wedding; he can't have forgotten. But although he seems to realize the urgency of getting to Juliet before she wakes up in three hours time, he takes his time about it, and only arrives at the exact moment Juliet wakes, and about a half-hour too late to save Romeo.

Answer 2

so she wont be sad about tyblats death. She would be happier with him until they marry.

Answer 3

The friar must rush to Juliet to prevent her from harming herself. He knows that trying to reunite her with Romeo is the best chance to resolve the tragic situation they are in.