Origen

“ But we ought to inquire whether the spirit of Elijah is the same as the spirit of God in Elijah, or whether they are different from each other, and whether the spirit of Elijah which was in him was something supernatural, different from the spirit of each man which is in him; for the Apostle clearly indicates that the Spirit of God, though it be in us, is different from the spirit of each man which is in Him, when he says somewhere, “The Spirit itself beareth witness with our spirit that we are the children of God;” ”

“ But some one might ask, if the soul of Elijah was not first in the Tishbite and secondly in John, what might that be in both which the Saviour called Elijah? And I say that Gabriel in his words to Zacharias suggested what the substance was in Elijah and John that was the same; for he says, “Many of the children of Israel shall he turn to the Lord their God; and he shall go before his face in the spirit and power of Elijah.” [3] For, observe, he did not say in the “soul” of Elijah, in which case the doctrine of transmigration might have some ground, but “in the spirit and power of Elijah.” ”