Outside in the church garden.
Friar Lawrence is picking herbs for his medicines when Romeo approaches him and asks for Friar to marry himself and Juliet. at first, Friar is startled and doesn’t think its a good idea but then agrees knowing it could bring the family’s together.
Romeo also says how herbs and men can be alike. how both have a good side and a bad side. quoting “Two such opposèd kings encamp them still, In man as well as herbs—grace and rude will.”
Then finally Friar Lawrence says to Romeo “Wisely and slow, they stumble that run fast.” Referencing how Romeo and Juliet are rushing into their relationship.