John Wesley on Genesis 35:20

And Jacob set up a pillar upon her grave - So that it was known long after to be Rachel's sepulchre, 1Sam 10:2, and Providence so ordered it, that this place afterwards fell in the lot of Benjamin. Jacob set up a pillar in remembrance of his joys Ge 35:14, and here he set up one in remembrance of his sorrows; for as it may be of use to ourselves to keep both in mind, so it may be of use to others to transmit the memorials of both.