Romeo's friends try hard to talk him into going to the Capulets' party. Mercutio tells him, "we must have you dance" (1.4.13). He accuses Romeo of being a spoilsport, as well as being overly cautious and "Up to the ears" in a love that is not fulfilling for him (1.4.43). Mercutio goes on a long rant about dreams, and that seems to shake Romeo up, changing the whole mood of the conversation. At this point, Romeo says,
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 breast
By some vile forfeit of untimely death.
But he that hath the steerage of my course,
Direct my sail. On, lusty gentlemen. (1.4.107-114)
In other words, Romeo has a feeling that the party will set his fate into motion and that it will initiate a sequence of events that will end in his own death. However, he says, whoever is in charge of his life's course urges him to go. And so he calls to his friends to depart, altogether, for the Capulets' house. Thus, it seems as though it is Romeo's premonition of his tragic fate that urges him toward the party; he feels as though he must go there.