At the beginning of Act IV, Juliet's father has arranged for her to marry Paris. When Paris goes to see Friar Laurence, though, the Friar does not want to marry Paris to Juliet.
The reason for Laurence's reluctance is because he has already married Juliet to Romeo in a secret ceremony in his cell. This happened in Act II, Scene 5.
Friar Laurence will go on to help Juliet avoid the wedding by giving her the potion that will make her appear to be dead. Unfortunately, Romeo will think she really is dead and will commit suicide because of it.
The reason for Laurence's reluctance is because he has already married Juliet to Romeo in a secret ceremony in his cell. This happened in Act II, Scene 5.
Friar Laurence will go on to help Juliet avoid the wedding by giving her the potion that will make her appear to be dead. Unfortunately, Romeo will think she really is dead and will commit suicide because of it.