Rashi on Genesis 31:51/רש"י על בראשית ל״א:נ״א

1יריתי I HAVE SET UP (by casting stones down); the word has the same meaning as (Exodus 15:4) “He cast (ירה) into the sea”. Laban speaks like a person who casts (יורה) one arrow (Midrash Rabbah has “one spear”) and boasts of his prowess.