I will make your offspring like the dust of the earth, so that if anyone could count the dust, then your offspring could be counted.
In context
14After Lot had parted from him, Yahweh said to Abram, “Lift up your eyes and look, from where you are, to the north, the south, the east, and the west. 15All the land you see, I will give to you and your offspring forever. 16I will make your offspring like the dust of the earth, so that if anyone could count the dust, then your offspring could be counted. 17Go, walk through the length and breadth of the land, for I am giving it to you.” 18So Abram moved his tent and went to live near the great trees of Mamre, at Hebron, where he built an altar to Yahweh.
