In the Bible, eating represents taking in knowledge and the desire for good. Trees represent knowledge and understanding that come from the Lord. So this verse says the people of the Most Ancient Church – "man" or "Adam" – were free to gather the knowledge that flowed to them from the Lord.

This happened in a way that we cannot truly understand now. Because the people of the Most Ancient Church were in a state of love to the Lord, they know instantly, from their affections, what was true. They didn't have to ponder logic and ask questions; they simply knew from their emotional response whether an idea was in accord with love to the Lord.

(Notae: Arcana Coelestia 0125)

125. Verse 16 And Jehovah God commanded the man and said, From every tree in the garden you may indeed eat.

'Eating of every tree' is recognizing and knowing, from perception, what good and truth are; for, as stated already, 'a tree' means perception. Members of the Most Ancient Church possessed the cognitions of true faith by means of revelations, for they talked to the Lord and to angels. They were also taught through visions and dreams, which to them were supremely delightful and blissful. They received perception from the Lord continually; and as a result of that perception, when they thought from things in their memory they instantly perceived whether these were true and good, insomuch that when anything false came up they not only had nothing to do with it but were also horrified. This is also the state of angels. Later on however knowledge of what is true and good took the place of the perception which the Most Ancient Church enjoyed, a knowledge based on what had been previously revealed, and later, on things revealed in the Word.