The proper noun Kush refers to the son of Ham (Genesis 10:6) and the land named after him — ancient Nubia, modern Sudan, and northeastern Africa. Known for powerful warriors, gold, and distinctive appearance. Greek writers called this region Ethiopia.
Psalm 68:31 envisions: 'Envoys from Egypt; Cush will submit her hands to God' — the nations worshiping the LORD. The Ethiopian eunuch of Acts 8 is an early fulfillment. Zephaniah 3:10: 'from beyond the rivers of Cush my worshipers will bring me offerings.' The margins of the earth will be gathered in.