“Every time I open a child's head and see a brain, I marvel at the mystery: This is what makes every one of us who we are. This is what hold all our memories, all our thoughts, all our dreams. This is what makes us different from each other in millions of ways.”

2013, Brandenburg Gate Speech (June 2013)

Nobel lecture (1989)

Variant: What are we after all our dreams, after all our memories?
Source: The Wedding

" Inaugural Address http://governor.maryland.gov/2015/01/21/inaugural-address-governor-larry-hogan/" (21 January 2015)

Source: How to Stop Worrying and Start Living

As rendered by T. Byrom (1993), Shambhala Publications.
There is no quote from the Pali Canon that matches up with any of these. The closest quote to this is in the Majjhima Nikaya 19:
"Whatever a monk keeps pursuing with his thinking & pondering, that becomes the inclination of his awareness. If a monk keeps pursuing thinking imbued with sensuality, abandoning thinking imbued with renunciation, his mind is bent by that thinking imbued with sensuality. If a monk keeps pursuing thinking imbued with ill will, abandoning thinking imbued with non-ill will, his mind is bent by that thinking imbued with ill will. If a monk keeps pursuing thinking imbued with harmfulness, abandoning thinking imbued with harmlessness, his mind is bent by that thinking imbued with harmfulness." Sources: http://www.accesstoinsight.org/tipitaka/mn/mn.019.than.html
Misattributed

Variant: What shall we do? All of us passionate girls who fear crushing the boys we love with our mouths like caverns of teeth, our mushrooming brains, and watermelon hearts?
Source: Blood Roses

2016, State of the Union address (January 2016)