《三国志·魏书·王卫二刘傅传》
之所以这样，是因为制度的建立应该考虑长远，也许并不贴近当前的现实，律法的制定应该符合实际情况，不一定能流传到后代。
所以然者，制宜经远，或不切近，法应时务，不足垂后。
The reason for this is that the establishment of the system should consider the long term and may not be close to the current reality. The formulation of laws should conform to the actual situation and may not be passed on to future generations.