业精于勤,荒于嬉;行成于思,毁于随。
Work becomes refined through diligence and falls into neglect through play; conduct succeeds through thought and is ruined by careless following.
Plain meaningDiligence needs reflection; effort without thought is not enough.
Original context and translation note
English wording on Gu Ren Said is an original reading aid, not a claim that there is only one valid literary translation.