Romeo and Juliet, Why are the nurse and friar Lawrence necessary to the plot of the play?

Each character (in good intentions) either encourages their love (the friar) or advises against it (the nurse). Friar Lawrence weds the two of them while the nurse (following her maternal instincts) continues to tell Juliet to forget Romeo.

I don't have a quote but you can honestly use any quote from the nurse and the friar when they are advising Romeo or Juliet about love.

The Nurse and Friar Lawrence are necessary to the plot of "Romeo and Juliet" because they serve as confidants and facilitators for the titular characters' relationship. The Nurse, as Juliet's trusted caretaker, provides support and guidance to Juliet in matters of love, aiding in the secret communication between Romeo and Juliet and helping them orchestrate their marriage. Friar Lawrence, a trusted confidant of Romeo, offers wise counsel and serves as the intermediary in Romeo and Juliet's secret marriage. Additionally, Friar Lawrence's role extends to providing the potion that allows Juliet to feign death, ultimately leading to the tragic outcome of the play. Therefore, both characters are indispensable to the development and resolution of the play's central conflict.