κένωσις started at creation

Yes, indeed, this is precisely the ultimate, and the real meaning of the divine Creation of the world. In the full sense of the word, God can only glorify Himself and lmpart Himself where a creature in freedom gives His word back to Him, the Word which He addresses to it, the word of love. Now we begin to see what a large measure of self-limitation He has imposed upon Himself, and how far He has emptied Himself, in order to realize this aim, to achieve it, indeed, in a creature which has misused its creaturely freedom to such an extent as to defy God. The κένωσις [kenosis, "emptying"], which reaches its paradoxical climax in the Cross of Christ, began with the Creation of the world.—Emil Brunner, The Christian Doctrine of Creation and Redemption, 20 (emphasis original)

<idle musing>
That is a mind-blowing throught! And then, thinking along the lines of what Brennan Manning pointed out about the eschaton, κένωσις endures throughout.

OK, that's totally mind-blowing, but then remember, we are called to be imitators of Christ. Guess what that means?

Hint: it doesn't mean taking over; it means servanthood. It doesn't mean being a "macho-man"; it means servanthood, κένωσις, emptying. It means cruciformity. Those ideas have never been very popular, have they? They could get a guy crucified—oh wait! They did.
</idle musing>