God created the earth with a clear purpose. It was not just to be inhabited, but was to be inhabited with people who would know him, know his glory - his perfect character, and willingly respond by seeking to develop that character in themselves.
If you want to be part of God's Kingdom then you have to respond now while there is still opportunity...
"He shall not judge after the sight of his eyes, neither reprove after the hearing of his ears: but with righteousness shall he judge the poor, and reprove with equity for the meek of the earth"
"And the work of righteousness shall be peace; and the effect of righteousness quietness and assurance for ever."
"...neither shall they learn war any more"
All of these remarkable things are only made possible when the earth is full of people and nations who are willingly educated and subject to God's ways and laws.
"and he will teach us of his ways, and we will walk in his paths: for out of Zion shall go forth the law, and the word of the LORD from Jerusalem"