Charles Ellicott Commentary Numbers 32:19

"For we will not inherit with them on the other side of the Jordan, and forward; because our inheritance is fallen to us on this side of the Jordan eastward." — Numbers 32:19 (ASV)

For we will not inherit with them on yonder side Jordan, or forward ... on this side Jordan eastward.— This is one of the critical passages that determine the meaning of the word that is rendered “on yonder side” in the first clause of the verse, and “on this side” in the second clause.

It is true that the meaning of the word in the first clause is defined by the addition of the word that is rendered “or forward,” and which is more correctly rendered and forward — that is, “further off,” or “to a greater distance.” Its meaning in the second clause is defined by the addition of the word “eastward,” or “towards the sun-rising.”

However, the application of the same word to the country on both sides of the Jordan shows that it cannot be inferred with any degree of certainty from the use of this word whether the writer's position was on the eastern or western side of the river. (See Numbers 32:32, where the same word occurs without any addition.)

The language of the Gadites and the Reubenites must not be interpreted as if it were spoken in a defiant spirit, but as disclaiming their right to any portion of the inheritance on the west of the Jordan if they obtained their request to settle on the eastern side.