The phrase "to fill the earth" means to populate or inhabit all parts of the world. It suggests that people should spread across different places and live in various areas, rather than concentrating in one specific location. Full definition
To fill the earth with the light and warmth of hospitality by delivering exceptional experiences — every hotel, every guest, every time. (hilton.com)
Let us be women willing to lay down our sword words, our sharp looks, our ignorant silence and towering stance and fill the earth now with extravagant Love. (rachelheldevans.com)