Stubborn and dull: spur stupidity and sharpen stupidity. It is extremely difficult to forge ahead.
Lu Peng takes off: Lu Peng: promising; Soar: fly. It is a metaphor for people to forge ahead in high expectations.
Born in sorrow, died in happiness: hardship makes people forge ahead, and ease makes people sink.
There is no end to learning: it means there is no end to learning, so we should keep making progress.