'Generations' in the Bible

but it shall be a witness between us and you, and between our generations after us, that we may do the service of Jehovah before him with our burnt-offerings, and with our sacrifices, and with our peace-offerings; that your children may not say to our children in time to come, Ye have no portion in Jehovah.

Therefore said we, It shall be, when they so say to us or to our generations in time to come, that we shall say, Behold the pattern of the altar of Jehovah, which our fathers made, not for burnt-offering, nor for sacrifice; but it is a witness between us and you.