The audience is introduced to Friar Laurence in Act 2, scene 3. He is out in the early morning gathering weeds, herbs, and flowers.
The scene and soliloquy are important to the play because the audience learns that Friar Laurence has experience with herbal remedies, potions, and natural drugs. He's a chemist as well as a holy man. The scene foreshadows his future involvement as a chemist and potion maker.
The scene also highlights Friar Laurence's philosophy of good and evil. Not only can nature be beautiful, but also it can be misused and corrupted. The Friar says that the reverse is also true. Good can come from evil. Misuse can be corrected and turned to fortune. All through his soliloquy though, an audience can suspect that the Friar is talking about more than nature and plants; however, Friar Laurence flat out says (at the very end of his soliloquy) that the whole "yin/yang/good/evil" philosophy does apply to people.
Two such opposèd kings encamp them still,In man as well as herbs—grace and rude will.