There is, for everyone, a crossroads when it comes to spiritual things, a basic decision to be made. Are you going to believe in the Lord and in spiritual reality? Or are you only going to believe what you can see, touch, feel and otherwise "know" from your own mind? The Writings say those who choose the latter course are closing themselves off from the truth, because by definition spiritual reality cannot be seen, touched, felt or otherwise "known" through purely human means. That's what it means to eat "of the tree of the knowledge of good and evil," and it leads to spiritual death – which is being cut off from the goodness and truth the Lord wishes to bestow on us.

The people of the Most Ancient Church were in a state of love to the Lord, and had been invited to gather all the wisdom and knowledge flowing from that love – the fruit of all the other trees. But they had to accept the Lord as the source, had to accept that He existed, had to accept that He was infinite and beyond their finite understanding. To think otherwise – to think that through their own minds they could explain the Lord – would be to put themselves above him, and lead them into evil.

It's worth noting that this was not a call for people to shut down their minds. The fruit of the other trees represents an incredible bounty of exploration, learning and wonderment. And we're not called on to shut down our minds today; the Lord gave us our intellectual faculties for a reason. To let the Lord in, though, we have to accept the unprove-able idea that He is love itself and reality itself, and see all other knowledge in that light.

(Referenties: Arcana Coelestia 126-132, 127, 128-134, 129, 0130)

Flesh has several meanings just in its most obvious form. It can mean all living creatures as when the Lord talks about the flood "destroying all flesh"(Genesis 7:21), or it can mean all of mankind (Genesis 6:3), or it can mean something soft and yielding such as the heart of flesh to replace the stony heart (Ezekiel 11:19) But spiritually it means the loves that dwell in the will of a person, and seem to belong to that person, to be that person. This person may be one who has not started to regenerate (or never will), or one who is in the middle of the process, or one who is near the end. In the highest sense flesh means the loves that are in the Lord's will, which are divine. This meaning is clear in the Lord's words in the gospel of John (John 6:53-56).