This quote is from the book, Meditations, by the Roman Emperor Marcus Aurelius. Meditations contains a series of notes and ideas by Aurelius to himself–a kind of personal journal. There is evidence to believe Aurelius suffered from chronic pain and poor appetite (symptoms of a possible ulcer). It was so bad that many were concerned for his health.
Knowing this context, we might have more appreciation for his words about waking up each morning with gratitude for simply being alive with the ability to think, enjoy, and love. It’s not always easy to do so, especially when we’re suffering from pain–be it physical or emotional. But perhaps, with gratitude, the pain can be lessened.