#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. They are spoken of as if they are human witnesses. (See: [[:en:ta:vol2:translate:figs_personification]])

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

Abraham is Jacob's grandfather. Nahor is Laban's grandfather. The father of Abraham and Nahor is Terah. Most likely, all of these men did not worship the same God.

#him whom his father Isaac feared

Here the word "feared" refers to the "fear of Yahweh," which means to deeply respect him and show that respect by obeying him.