Jesus responded and said to him: "What I am doing, you do not now understand. But you shall understand it afterward.
Other versions
King James Version
Jesus answered and said unto him, What I do thou knowest not now; but thou shalt know hereafter.English Standard Version
Jesus answered him, "What I am doing you do not understand now, but afterward you will understand."New International Version
Jesus replied, "You do not realize now what I am doing, but later you will understand."