A.T. Robertson Commentary Romans 9:12

"it was said unto her, The elder shall serve the younger." — Romans 9:12 (ASV)

But of him that calleth (αλλ' εκ του καλουντος). Present active articular participle of καλεω in the ablative case after εκ. The source of the selection is God himself. Paul quotes Ge 25:33 (LXX).