December 3

…the change and modification of conditions, and the altered requirements of different centuries and times, are the cause of the abrogation of laws. For a time comes when these laws are no longer suitably adapted to conditions. Consider how very different are the requirements of the first centuries, of the Middle Ages, and of modern times. Is it possible that the laws of the first centuries could be enforced at present? It is evident that it would be impossible and impracticable. In the same manner, after the lapse of a few centuries, the requirements of the present time will not be the same as those of the future, and certainly there will be change and alteration. In Europe the laws are unceasingly altered and modified; in bygone years, how many laws existed in the organizations and systems of Europe, which are now abrogated! These changes and alterations are due to the variation and mutation of thought, conditions and customs. If it were not so, the prosperity of the world of humanity would be wrecked.

For example, there is in the Pentateuch a law that if anyone break the Sabbath, he shall be put to death. Moreover, there are ten sentences of death in the Pentateuch. Would it be possible to keep these laws in our time? It is clear that it would be absolutely impossible. Consequently, there are changes and modifications in the laws, and these are a sufficient proof of the supreme wisdom of God. 
(‘Abdu’l-Baha, table talks in Akka, authenticated by ‘Abdu’l-Baha; ‘Some Answered Questions’)