I came out from the Father (exēlthon ek tou patros). Definite act (aorist), the Incarnation, with repetition of ek (out of), while in Joh 16:27 we have (para tou patros exēlthon) with no practical distinction between ek and para in resultant idea.
Am come (elēlutha). Perfect active indicative of erchomai, as in Joh 18:37. The Incarnation is now a permanent fact, once only a blessed hope (Joh 11:27). His leaving the world and going to the Father does not set aside the fact of the Incarnation. Both aphiēmi (I leave) and poreuomai (I go) are futuristic present indicatives.