Sometime after the fall of Jerusalem, with its destruction of the Temple, God showed Ezekiel a vision of the new Temple, with detailed plans and measurements. The reason:
Ezekiel 40:4 … Son of man, watch and listen. Pay close attention to everything I show you. You have been brought here so I can show you many things. Then you will return to the people of Israel and tell them everything you have seen.
Even in a time of severe discipline, God didn’t abandon His people, finding a way, instead, of giving them hope.