In some ways, this verse expresses the pinnacle of human existence, the most beautiful, joyous state we have ever experienced: people at their purest and most loving living in a state of love and wisdom given them by the Lord.

This happened thousands of years ago, before the beginning of recorded history, in what the Writings call the Most Ancient Church, represented here by "man." A garden represents the intellect and Eden represents love, so the man in the Garden of Eden represents people pure of heart in a state of love to the Lord and the wisdom that comes from that love.

It's interesting that the man is to "dress" the garden ("serve" would be a more literal translation) and "keep" it. "Serving" in the Bible generally represents a more external spiritual state serving a more exalted one. "Keeping" means expressing higher spiritual things through lower ones, including external forms of worship. It seems, then, that the people of the Most Ancient Church were to serve the love in the garden and express the wisdom coming from that love.

The Writings also say directly that this means the love and the wisdom were not their own, but were from the Lord, and that they knew it to be true.

(References: Arcana Coelestia 122, 123, 124)

To “generate” something is to create it, and that idea underpins the meaning of a “generation” of people -- it is a group that was created together, at roughly the same time, from the same parents or group of parents. On a spiritual level, we can be “generators” by using what we know from the Lord to create ideas of how to be good, and also to create good actions based on those ideas -- what the Writings call things of faith and things of charity. In general, then, a “generation” in the Bible represents the spiritual ideas and activities created by a church -- with a “church” being anything from an individual believer to a group lasting thousands of years. “Generation” can also pick up specific meanings from context. For instance, when the Bible says the people of Israel were captive in Egypt for four generations, it means a state of temptation based on the meaning of “four.” When paired with “eternity,” meanwhile, “generations” represents ideas and actions surrounding love of serving others, with “eternity” representing things springing from love of the Lord. Finally, “generations and generations” is used in the Bible to represent forever.