"Romeo slew Tybalt; Romeo must not live."(Lady Capulet)
"Not Romeo, Prince; he was Mercutio's friend. His fault concludes what the law should end, the life of Tybalt." (Montague)
When the families are arguing about Romeo's punishment
Immediately we do exile him hence... I will be deaf to pleading and excuses. Nor tears nor prayers shall purchase out abuses. Therefore use none.(Prince)
This symbolizes opposing forces because the two families are really opposites. And in this scene they are arguing which just makes the tension so high. Along with the fact that its over a very important thing.
"Ay me" (Juliet)
In this part of the scene, Montague says what he thinks should happen, much to the displeasure of Lady Capulet. Knowing these two are polar opposites, its really shows opposing forces. The tension is still extremely high here.
"Shall I hear more, or shall I speak at this?"(Romeo)
This is where the Prince comes up with a final decision that ends up making people unhappy. Another interesting part about this part of the scene is that the Prince is introduced which is another force that opposes the others. This helps support the motif of opposing forces even more.
When Romeo sneaks back into the Capulet garden
"O Romeo, Romeo, wherefore art thou Romeo? Deny thy father and refuse thy name, or; if thou wilt not, be but sworn to my love, And I'll no longer be a Capulet" (Juliet)
This is important because Juliet is talking about Romeo and doesn't know that he is indeed there. We know these two are from different families. This makes it so they represent different things and it shows opposing forces
This part shows the motif because we see that Romeo is there but hasn't made himself known to Juliet yet. This means that he is sort of playing with her which is something that shows opposing forces. The fact that he isn't making himself known is important.
This part of the scene is very important in showing the motif because Juliet knows that she shouldn't be with Romeo. She even acknowledges that the families are opposing and that if she marries Romeo, she will no longer be a true Capulet. This shows the opposing forces motif very well because you can see the families "clashing" here.