In other words, in Abraham’s time it was impossible for humans to know how many would make up this seed.
قِيلَ لِإِبْرَاهِيمَ إِنَّ نَسْلَهُ سَيَكْثُرُ وَيَصِيرُ « كَنُجُومِ ٱلسَّمَاءِ » وَحَبَّاتِ ٱلرَّمْلِ عَلَى شَاطِئِ ٱلْبَحْرِ .‏