The Lord God Almighty needs to hear singing in the earth. He needs to hear the spirit of those who are in the millennial kingdom singing praises to God, not only because his kingdom has come, but also because the Lord God Almighty is in the earth.
He himself is in the earth, and he himself will close the door to his kingdom. If you are not in it, and you have no plan of repentance scheduled during the next few days, you will likely be left out of his millennial kingdom. The Lord God Almighty is El Shaddai.