John 21:22
If I will (ean qelw). Condition of the third class with ean and the present active subjunctive of qelw.
Till I come (ewv erxomai). Literally, "while I am coming" (ewv and the present indicative, not ewv elqw (second aorist active subjunctive).
What is that to thee? (ti prov se). A sharp rebuke to Peter's keen curiosity.
Follow thou me (su moi akolouqei). "Do thou me keep on following." That lesson Peter needed.
