I have sometimes thought that Jesus' resurrection and Ascension was made evident to Mary and the other disciples in their ordinary lives in part to demonstrate that there is no real dividing line between the Kingdom here and now and the the Kingdom there and then. Think of the Kingdom of God as a house. The death of our present bodies is simply a door leading from one living room of the Kingdom to another. But they are rooms in the same house.
After all, Jesus could have been raised from death and he could have returned to the Father with no witnesses to either event. The Holy Spirit could still have come and if Gabriel had appeared before the disciples and announced Jesus raised and ascended I think they would have believed.
But instead, Jesus died and was raised in "this room" of the eternal House of God. He lived, and lived again, in this time and this place - and the same Jesus who did that then ascended bodily to the "other room" of the House of God. There is a distinction between the two rooms, but it is a weak distinction. What they have in common is far stronger.
That said, I think that Dallas Willard overstates his point. I know one danger is to be so heavenly minded we will be of no earthly good. But I disagree that the Gospels are "less" about eternal salvation than right living now. I do not think that Jesus made that distinction. It is one, single Kingdom and he preached to live it in starting now. But he never said that "getting to Heaven" was less important than right living now. In fact, I think that such a statement would have struck Jesus as nonsensical.
I would have us bear in mind what C.S. Lewis said in "The Problem of Pain,"
We are very shy nowadays of even mentioning Heaven. We are afraid of the jeer about "pie in the sky," and of being told that we are trying to "escape from the duty of making a happy world here and now into dreams of a happy world elsewhere." But either there is "pie in the sky" or there is not. If there is not, then Christianity is false, for this doctrine is woven into its whole fabric. If there is, then this truth, like any other, must be faced, whether it is useful at political meetings or not.
And from "Mere Christianity:"
Aim at Heaven and you will get earth ‘thrown in’: aim at earth and you will get neither. It seems a strange rule, but something like it can be seen at work in other matters. Health is a great blessing, but the moment you make health one of your main, direct objects you start becoming a crank and imagining there is something wrong with you. You are only likely to get health provided you want other things more—food, games, work, fun, open air. In the same way, we shall never save civilisation along as civilisation is our main object. We must learn to want something else even more.
It may be argued - and in fact, my colleague Joey Reed does so argue - that Lewis also overstated his case. As Joey wrote,
The Kingdom of Heaven is rich enough to extend from the past to the present to the future. Those who relegate it to one or the other have chosen chocolate or vanilla or strawberry when the box clearly says "Neapolitan".
It's all one box of ice cream. In Joey's and my Wesleyan tradition, we avoid over-concentrating on which room of the house we are in by staying on balance in Christian discipleship. I did not originate this diagram, but is captures what healthy discipleship is:Discipleship is not either-or one side or one level, but not the other. It is both-and. If we overemphasize piety, we risk morphing into "I got mine" Christians, whom Jesus quite specifically said in Matthew 25 he would eject from his presence. If we overemphasize works of mercy, we risk developing a messiah complex of our own, thinking that the Kingdom can be realized here and now in its entirety and that society can be perfected by ourselves - especially by politics apart from God-Christ-Church. And good luck facing Jesus with that.
This gospel seeks us and justifies us exactly as sinners. Admit your sin boldly; do not try to flee from it, but ‘believe much more boldly.'
We must not be so heavenly minded that we are of no earthly good. But we must never be so earthly good that we omit ourselves and others from the eternal kingdom.