You can read the entire text of the letter here. From the end:

Our country has always been strongest when we come together. We feel the best way forward would be for the government to withdraw its demands under the All Writs Act and, as some in Congress have proposed, form a commission or other panel of experts on intelligence, technology and civil liberties to discuss the implications for law enforcement, national security, privacy and personal freedoms. Apple would gladly participate in such an effort.

People trust Apple to keep their data safe, and that data is an increasingly important part of everyone’s lives. You do an incredible job protecting them with the features we design into our products. Thank you.

Amazing to watch the CEO of one of the largest companies in the world take such a strong stance based on personal beliefs.