This pile is a witness between me and you
The stones do not actually bear witness as a person. AT: "This pile will be a reminder between me and you" (See: rc://en/ta/man/translate/figs-personification)
Translators may add a footnote that says: "The name Galeed means 'heap of witness' in Jacob's language. See how you translated this in Genesis 31:47. (See: rc://en/ta/man/translate/translate-names)
Translators may add a footnote that says: "The name Mizpah means 'watchtower.'" (See: rc://en/ta/man/translate/translate-names)
when we are out of sight one from another
Here "out of sight" stands for no longer being in each other's presence. AT: "when we are no longer with each other" (See: rc://en/ta/man/translate/figs-metonymy)
although no one else is with us
Here "us" refers to Laban and Jacob. AT: "even if no one else is there to see us"
"remember." This adds emphasis to what is said next.