[cóng shàn rú dēng]   

从    善    如    登    指为善如登山那样不易，比喻学好很难。

从善如登山：登：升高。顺从好的就像登高一样，比喻学好不容易，要花力气，表示做好事很不容易。

To pursue goodness is as difficult as ascending a mountain

从轻处罚    从古到今    从善如登    从长计议    从头至尾