THat which is inside where he is hoping to point the way to and the bible is pointing the way to...IS Christ. The kingdom is within. I knew this when I was a child and I lost it and now I am finding it again. BE STILL AND KNOW THAT I AM GOD. It’s inside ourselves. Also I believe the author means that the people of Germany and alas...here in the United States were deceived into thinking they were children of God when they weren’t so they were powerless to do anything when they realized what was happening. It’s like being in a cave and seeing the light on the wall from the sun outside. You think you know what the sun is, but its not until you step outside and see it and feel that you can know it.
I don’t see it that the Bible teaches that the kingdom of God is within.
I don’t pretend that the kingdom of God is utterly clear cut in Scripture. It is an intricate concept, for sure. But I don’t think it can be said that the Bible teaches that the kingdom is within us.
I am also skeptical of pointing the way to Christ without mentioning Him.
Again, all that said...I think there is plenty here for a Bible-believing Christian to make use of. I do agree that this sort of therapeutic/inward looking approach has some utility. Just why are we (ie, I, you, others, everyone) neurotic? There is some utility to trying to know yourself. But that is not absolutely necessary. The bottom line is that, as taught in Scripture, we have to know that we are sinners, in need of Christ, and that we should take every thought captive in obedience to Him. To know Him, we must know the Bible and meditate on it day and night. We must be ambitious in that regard.
And to that end....should we be aware of the awful tendency of sinful humans to resentment? Yes, indeed, we should. The author is doing a service in pointing that. Resentment (the very foundation of liberalism) is truly a deadly sin. We MUST attack it and root it out.
(But only Jesus can do that for us.....).