I am come down (katabebhka). Perfect active indicative of katabainw. See on Jo 33 for frequent use of this phrase by Jesus. Here apo is correct rather than ek with tou ouranou. Not to do (ouc ina poiw). "Not that I keep on doing" (final clause with ina and present active subjunctive of poiew). But the will (alla to qelhma). Supply ina poiw after alla, "but that I keep on doing." This is the fulness of joy for Jesus, to do his Father's will (Jo 4:34; Jo 5:30).