We have not always been in sync on every issue in terms of our core values, in terms of her integrity, her truthfulness, her thoughtfulness, [Angela Merkel] doing her homework, knowing her facts, her commitment to looking out for the interests of the German people first, but recognizing that part of good leadership on behalf of the nation requires engaging the world as a whole, and participating effectively in multilaterally institutions, I think she's been outstanding.

More than a building that houses books and data, the library represents a window to a larger world, the place where we've always come to discover big ideas and profound concepts that help move the American story forward and the human story forward.

Any so-called leader who does not take this issue (climate change) seriously or treats it like a joke is not fit to lead

I believe that the free enterprise system is the greatest engine of prosperity the world's ever known.

Your ability to let go is part of the duty that you have.

While we breathe, we will hope.

Angela [Merkel] and I also agreed the need for a comprehensive and humane response to the devastating humanitarian crisis in Syria and for the influx of migrants and refugees from around the world. We need to build on the progress achieved at the U.N. Refugee Summit, which yielded new commitments from some 50 nations and organizations.