en_tn_condensed/jos/22/27.md

to be a witness between us and you

The altar is spoken of as if it were a witness that could testify to the rights of the three tribes. (See: rc://en/ta/man/translate/figs-metaphor)

so that your children will never say to our children in time to come, "You have no share in Yahweh."

This is the hypothetical situation that the three tribes did not want to happen. (See: rc://en/ta/man/translate/figs-hypo)

no share

"no portion" or "no inheritance"