I have an essay for Romeo and Juliet, asking if Friar Laurence should be punished for his involvement in the marriage. I said that he shouldn't be punsihed because he was trying to end the feud and that Romeo and Juliet would have still be together even if their parents didn't know. I need one more reason. Any ideas?

As a cleric, maybe he is immune from punishment regarding his religious acts?

http://www.sparknotes.com/shakespeare/romeojuliet/canalysis.html

Definitely! Building on the points you've mentioned, here's another reason you can consider for why Friar Laurence should not be punished for his involvement in the marriage of Romeo and Juliet:

3. Intentions to reconcile feuding families: Friar Laurence's primary motive for marrying Romeo and Juliet was to bring an end to the longstanding and bitter feud between the Montagues and Capulets. By uniting the young couple in matrimony, he hoped to create harmony and unity among the two families. His intention was to foster peace and find a peaceful resolution to the conflict that had plagued Verona for years. Punishing Friar Laurence for his role in the marriage could be seen as unjust, as it ignores his genuine efforts to reconcile the families and ultimately bring peace to the city.

Incorporating this additional reason into your essay will strengthen your argument by highlighting the Friar's genuine and well-meaning intentions. Remember to support each reason with evidence from the play, such as specific dialogue or actions of Friar Laurence that demonstrate his desire to end the feud.