Romeo and Juliet begins with a fight between the servants of the Capulets and Montagues. The play opens with Sampson and Gregory. two Capulet servants, walking down a Verona street discussing that they would like to start a fight with the Montagues and what they would do if they walked into them. Since the sidewalks are small, the weaker servants are to move aside, so since they are servants for the house of Capulet, they believe they are too strong to move it.
SAMPSONA dog of the house of Montague moves me. GREGORY To move is to stir, and to be valiant is to stand. Therefore if thou art moved thou runn’st away. SAMPSON A dog of that house shall move me to stand. I will take the wall of any man or maid of Montague’s. GREGORY That shows thee a weak slave, for the weakest goes to the wall
Once the two run into the Montague servants, they begin trading insults and antagonizing them until the Montague servant, Abram, takes the bait to start the fight.
By opening the play with a fight between the servants, Shakespeare is showing us the depths of the feud, Not only do the Montagues and Capulets hate one another, but that hatred trickles down to their servants.
The conversation between Sampson and Gregory, two servants of the house of Capulet, make it clear that they are out to provoke the Montagues, their masters' lifelong enemies, into a fight. They speak about how much they hate the Montagues and how they would fight them in an encounter. When they see two Montagues, Abraham and Balthasar, approaching, they decide to start a quarrel:
I will frown as I pass by, and let them take it as
Nay, as they dare. I will bite my thumb at them;
which is a disgrace to them, if they bear it.
Sampson is clearly intent on daring the two men and decides to make an insulting gesture which, he knows, would offend the two and draw them into a confrontation. He bites his thumb, which is a vulgar indication of his disrespect for the two men. Abraham questions his action and Sampson at first denies the gesture but then states that he is, after all, biting his thumb. Gregory then asks Abraham if he is quarreling, an accusation that he denies.
Sampson, for his part, informs Abraham that he is for him, since he is employed by a master similar in status to his. He will, therefore, not stand back and tolerate any abuse. Abraham's response, "no better," is a clear insult (he claims that his master is better than theirs or that they are equal in status). The two Capulet servants then insist that he acknowledge the superiority of the house they serve, and when he refuses and tells them that they are lying, Sampson then challenges them to a duel:
Draw, if you be men. Gregory, remember thy swashing blow.
Sampson has probably just noticed Tybalt, also of the Capulet house, on his way, and is obviously emboldened. The men start fighting and Benvolio (a Montague) steps in and attempts to stop the fight. Tybalt then arrives and threatens him. The fight soon spreads and a number of supporters from both houses join in the fray, including lords Montague and Capulet.
It should be obvious that the chief perpetrator in this incident is Sampson. He took the lead throughout and was intent on creating a fracas, continuously confirming with Gregory whether they would have the law on their side and then succeeding in his nefarious purpose.