This verse gives the words of a treaty between the two men: neither side will cross the boundary to do the other harm. This is different than the words of the treaty given in verse 50.

This heap is a witness, and the pillar is a witness: see Good News Translation, which reduces these two clauses to one.

That I will not pass over this heap to you: this statement is completed in Revised Standard Version only at the end of the verse, where the words for harm are found. It will often be necessary to move the purpose forward by saying, for example, “I will never go beyond this pile to injure you.” See Good News Translation. New English Bible says “… to do an injury,” which Revised English Bible has revised to “with evil intent.” In many languages this is most simply expressed as “to cause you harm.” Some languages have special terms or expressions for crossing over tribal or national borders, or markers for ownership of land; such terms and expressions will generally be appropriate in this context.

And you [Jacob] will not pass over …: here the pillar is added. Otherwise the only change from the statement before is the change of the pronoun, you (singular).

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Genesis. (UBS Helps for Translators). New York: UBS, 1997. For this and other handbooks for translators see here .