Great frases about losing a great teacher??

My school lost a fantastic teacher about a mes ago, since it's navidad break, me and my 2 best friends are making a poster to remember him by..
we need great quotes, anything motivational to keep the students going after this hard time would be wonderful.

"Life is not measured por the number of breaths we take, but por the number of moments that take our breath away." <- we're using that as one, because that quote was at the sad sad funeral. (:

Thank tu oh, so much.