## This pile is a witness, and the pillar is a witness ##

These piles of stones were to act as a remembrance and a boundary marker for Jacob and Laban regarding their peace agreement.

## May the God of Abraham, and the God of Nahor, the God of their father, judge between us ##

The word "God" is plural in this context. Since Laban worshipped several gods he was making a general promise that included the gods from both their grandfathers. Alternate Translation: "May Abraham's gods and Nahor's gods and their father's gods, judge between us."