Why did Jacob name the place Peniel or Phaneel?
Jacob named the place Peniel or Phaneel because, as the context records, he declared, "I have seen God face to face." He recognized that the wrestling encounter was a theophany, a pre-incarnate appearance of God the Son, and he commemorated the place accordingly.
Les explains that Jacob called the place Phaneel because he said, "I have seen God face to face." Les points out that this was a theophany, an appearance of God the Son, not the Trinity or the invisible Godhead. He notes that no man has seen the triune God and lived, but God the Son appeared throughout the Old Testament, as with Abraham in Genesis 18 and the burning bush. So Jacob named the place to commemorate seeing God face to face, and the verse continues with the thought of his life being preserved.
And Jacob called the name of the place Peniel: for I have seen God face to face, and my life is preserved.