“Fruit” in the Bible generally represents what we produce, the things we actually make and do. “Ground” generally represents things that are external, the visible outer layer of people or things.
The meaning of “fruit of the ground,” then, generally represents things that are externally good but limited, with more precise meanings depending on the fruit in question and the ground in question. In Genesis, Cain represents spiritual belief and knowledge that lacks a desire for what is good, so when he makes an offering of the fruit of the ground, it represents things done dutifully in a dry, loveless spirit. But when the phrase is used by various prophets, the “ground” typically means the external knowledge of a church inspired by an internal love of the Lord and of others. In those cases the fruit is positive, the end result of a desire for good expressed through outward ideas.
Arcana Coelestia (Elliott) n. 348
348. ‘The fruit of the ground’ is used to mean the works of faith devoid of charity. This also is evident from what follows. In effect the works of faith devoid of charity are the works of no faith at all. In themselves they are dead since they belong purely to the external man.
AE 710; 23
“Blessed be the fruit of thy belly, and the fruit of thy ground, the young of thine oxen, and of the sheep of thy flock” (Deut. xxviii. 4).
These words were spoken to the sons of Jacob, who understood them only naturally, that is, according to the sense of the letter, because they were completely natural, and not in the least degree spiritual. But those blessings signify spiritual blessings, which pertain to heaven, and thus to eternal life – the fruit of the belly signifying the good of love and the truth of that good; the fruit of the ground, everything pertaining to the church; the corn and new wine (mustum), all good and truth in the natural man; the young of oxen, and of the sheep of the flock, their affections, exterior and interior. In general all those things signify the fructification and multiplication of truth and good.
AE 304; 39
[39] In Malachi:
He shall not destroy for you the fruit of the ground, neither shall the vine in the field be barren to you; all nations shall proclaim you happy, and ye shall be a land of good pleasure (Mal. 3:11-12).
These things are said of those with whom is the church; and because “the fruit ofthe ground,” and “the vine in the field” signify the goods and truths of the church (“fruit” goods, and “the vine” its truths), therefore they are called “a land of good pleasure.”