Friar Lawrence is often the character in Romeo and Juliet that aid their love, and he constantly concerned in play, even when we first meet him, about the well being of Verona. He is also not worried about the way it is affecting the whole of society as we see in act 1 scene 1, but also the young when he states in act 2 scene 3 "Virtue itself...action dignified," he later does many things that makes himself involved in the love of Romeo and Juliet.
The Friar first involves himself directly after we first meet him in act 2 scene 3, when he encounters Romeo, we know from him speaking that he does not believe that Romeo's love for Juliet is pure, when he states of Rosaline's relationship with him "Is Rosaline...in their eyes." However the Friar consents to marry them for a good cause "For this alliance...pure
love" in the hope that it may force both families to put aside their hate, and love one another. When the Friar actually marries the two lovers in scene 6 he imparts to Romeo a piece of advice, "These...as too slow" meaning that he is comparing them to things that react too quickly and to things that turn sour when done too much, for example honey, in doing so he advises them to love moderately.
After Romeo kills Tybalt the Friar consults Romeo, and tells him that instead of the Prince choosing execution as punishment, he had decided upon banishment. Romeo, after hearing this, said that this was worse than death "There is no world...stroke that murders me." After which the Friar scowls him "O deadly sin...seest it not", and later says that in a long speech about how well fortune had looked down on him "Thy Juliet is alive...A...