Depends which scene. At the end of Act 2 he marries them, if that is what you are asking about.
Juliet says, "Romeo, I come! This do I drink to thee!" and she drinks Friar Lawrence's potion.
Friar Lawrence's plan at the end of Act 3, Scene 3 in "Romeo and Juliet" is for Romeo to spend the night with Juliet and then leave for Mantua in the morning. The Friar hopes this will allow Romeo and Juliet to eventually be reunited and that their marriage will bring an end to the feud between the Capulets and Montagues.
"Wisely and slow; they stumble that run fast."He says it in Act II in the scene after the Balcony. Romeo visits Friar Lawrence's cell to ask him if he will marry Romeo and Juliet. It is at the end of this scene with Romeo and the Friar where this said.
Friar Laurence confesses to Friar John at the end of Romeo and Juliet. He reveals the truth about his role in the tragic events that led to the deaths of Romeo and Juliet.
At the end of scene two, Friar Lawrence plans to marry Romeo and Juliet to try and end the feud between their families. He also hopes this union will bring peace to Verona.
Friar Laurence in Romeo and Juliet, appears to play a small role, because of his mere seven scenes. However, closer examination reveals that the Friar plays a fundamental role in the development of the story. He is a confidant to Romeo, moves the plot, and is instrumental to the tragedy at the end of the play. At the beginning of the play the reader learns that Friar Laurence and Romeo are close friends. After Romeo explains to the Friar his love for Juliet, he tells him that him and Juliet must marry to end the feud between the two families. Also, his plan to make Juliet sleep for 48 hours while Romeo comes and takes her away, failed. He is the reason behind Romeo and Juliets death. _NOUR SOLIMAN_
Friar Laurence advices moderation in love, not violent excess. Then Romeo, Juliet and Friar Laurence leave to get married.
In Act 3, Scene 3 of "Romeo and Juliet," Friar Laurence displays a fault of being overly optimistic and naive in his belief that Romeo and Juliet's marriage can bring an end to the feud between their families. He fails to anticipate the tragic consequences of their secret relationship and rushed marriage.
The nurse instructs Juliet to go to Friar Laurence's cell to be married to Romeo secretly. She will then go to Romeo's house where they will consummate their marriage and plan for their future.
In the end of the scene, Friar Lawrence gives Romeo a plan to reunite with Juliet by faking his own death and then running away together once he is safely in Verona. This plan involves taking a potion that will make him appear dead for 42 hours and then sending a letter to inform Juliet of the situation.
Juliet threatens to end her own life in scene 5 of Romeo and Juliet.
First he's going to Juliet's bedroom, to spend the night with her, then he's going to go to Mantua, to wait for Friar Laurence to arrange for his return.