a learning both sound in theory and practice
It is a Chinese idiom. Pinyin is n è ISH è NGW à IW à ng, which means having the talent and virtue of a saint on the one hand and being able to carry out the kingly way on the other. This is the political thought of Taoism. It comes from Zhuangzi · Tianxia.
The origin of Idioms
Zhuangzi · Tianxia written by Zhuangzi in the pre Qin period and Zhuangzi in the Zhou Dynasty: "it's the way of inner sage and outer king. It's dark but not clear. It's melancholy but not clear. The people in the world are what they want, and they take their own way."
Idiom usage
In Ming and Li Zhi's four book reviews University: "true knowledge, true economy, with this book."
a learning both sound in theory and practice
destroy the old and establish the new - pò jiù lì xīn
forget sb . 's past error and forgive him - lüè jì yuán xīn