King James Version (KJV)
And the children of Reuben and the children of Gad called the altar {Ed}: for it {shall be} a witness between us that the LORD {is} God. {Ed: that is, A witness}
Modern English
The children of Reuben and the children of Gad named the altar “A Witness Between Us that Yahweh is God.”
Hebrew
וַֽיִּקְרְא֛וּ בְּנֵי־רְאוּבֵ֥ן וּבְנֵי־גָ֖ד לַמִּזְבֵּ֑חַ כִּ֣י עֵ֥ד הוּא֙ בֵּֽינֹתֵ֔ינוּ כִּ֥י יְהוָ֖ה הָאֱלֹהִֽים׃
vayiqrʾv bney-rʾvben vbney-gad lamizbeḥa kiy ʿed hvʾ beynoteynv kiy yhvah haʾelohiym