Contrary to nature (para phusin). This is the gist of the argument, the power of God to do what is contrary to natural processes. He put the wild olive (Gentile) into the good olive tree (the spiritual Israel) and made the wild olive (contrary to nature) become the good olive (kallielaios, the garden olive, kallos and elaia in Aristotle and a papyrus).
Into their own olive tree (tēi idiāi elaiāi). Dative case. Another argument a fortiori, “how much more” (pollōi mallon). God can graft the natural Israel back upon the spiritual Israel, if they become willing.