Ezekiel 36:38
As the holy flock, as the flock of Jerusalem in her solemn feasts; so shall the waste cities be filled with flocks of men: and they shall know that I am the LORD. As the holy flock, as the flock of Jerusalem in her solemn feasts; so shall the waste cities be filled with flocks of men: and they shall know that I am the LORD.
After cleansing his people from their iniquities, God will restore the ruined and waste cities. He will fill them with flocks of people as densely as Jerusalem is filled with the holy flock gathered for its solemn appointed feasts. This cleansing, restoration, and filling will cause those who behold it to know that he is the Lord.