King James Version (KJV)
Thou shalt know also that thy seed shall be great, and thine offspring as the grass of the earth.
Modern English
You shall know also that your offspring shall be many, and your descendants as the grass of the earth.
Hebrew
וְיָדַעְתָּ֣ כִּי רַ֣ב זַרְעֶ֑ךָ וְ֝צֶאֱצָאֶ֗יךָ כְּעֵ֣שֶׂב הָאָֽרֶץ׃
vyadaʿta kiy rab zarʿeka vṣeʾeṣaʾeyka kʿesheb haʾareṣ