'A seed' signifies the ultimate and primary levels in a person. It also signifies good and truth from the Lord. In an opposite sense, it signifies falsity of doctrine and hellish falsity. 'A seed' signifies everyone who constitutes the Lord's spiritual kingdom and faith grounded in charity.

In Genesis 12:7, 8:15, 16, 'a seed' signifies love and everyone who has love.

(Riferimenti: Arcana Coelestia 1025)

1025. That 'with your seed after you' means those who are being created anew is clear from the meaning of 'seed' and also from what follows. It is clear from the meaning of 'seed', in that in the literal sense 'seed' means descendants, but in the internal sense faith; and because faith, as stated often, does not exist except where charity does so, it is charity itself that is meant in the internal sense by 'seed'. And from what follows it is clear that not only the person inside the Church is the subject but also he who is outside the Church, and so the whole of the human race. Wherever there is charity, even among gentiles furthest away from the Church, the seed is there, for heavenly seed is charity. Indeed nobody at all can do anything good from himself; everything good comes from the Lord. The good that gentiles do, who in the Lord's Divine mercy will be dealt with later on, also comes from the Lord. That the seed of God is faith has been shown already in 255. By faith, there and in other places, is meant charity from which faith flows, for no faith that is really faith exists apart from faith that is an expression of charity.

[2] The same applies elsewhere in the Word where 'seed' is mentioned; for example, where the seed of Abraham, or Isaac, or Jacob is referred to, love or charity is meant. Actually Abraham represented celestial love, Isaac spiritual love, both of which belong to the internal man, while Jacob represented the same as they exist with the external man. This applies not only in prophetical but also in historical sections. In heaven it is not the historical descriptions of the Word that are perceived but the things that those descriptions mean, for the Word has been written not only for the sake of man but also for that of angels. When man reads the Word and gains from it no more than the literal sense, the angels do not gain the literal sense but the internal sense. The material, worldly, and bodily ideas man has when reading the Word become with angels spiritual and celestial ideas. While man is reading about Abraham, Isaac, and Jacob, for example, the angels do not have Abraham, Isaac, or Jacob in mind at all but those real things which are represented and so meant by them.

[3] The same applies with Noah, Shem, Ham, and Japheth. Angels have no knowledge of those people nor do they perceive anything else but the Ancient Church. More interior angels do not even perceive the Church, but the faith of that Church, and according to the train of thought they perceive the state of the things under discussion. Thus when 'seed' is mentioned in the Word, as here in reference to Noah, in the statement about the covenant being established with them and with their seed after them, angels do not perceive the descendants of those persons, for the man Noah never existed, only the Ancient Church bearing that name. By 'seed' angels understand charity, the essential constituent of the faith of that Church. The same applies to the historical details concerning Abraham, Isaac, and Jacob; when their seed is mentioned angels in no way understand the actual descendants of those three but all people throughout the world - both those who are inside the Church and those who are outside - with whom heavenly seed, which is charity, resides. And indeed the more interior angels perceive love itself, which is the heavenly seed - by itself, abstractly.

[4] That 'seed' means love and also everyone who has love is clear from the following places which refer to Abram,

Jehovah said, To your seed I will give this land. Genesis 12:7.

And also,

All the land which you see I will give to you and to your seed even for ever. And I will make your seed as the dust of the earth. Genesis 13:15-16.

People who keep to the sense of the letter grasp no more than this - that 'seed' is used to mean Abram's descendants, and 'land' to mean the land of Canaan, especially as that land was given to his descendants. But people possessing the internal sense, as the whole of heaven does, perceive 'the seed of Abram' to be nothing other than love, 'the land of Canaan' as nothing other than the Lord's kingdom in heaven and on earth, and 'the land' being given to them as nothing other than its representative, which in the Lord's Divine mercy will be dealt with elsewhere. A similar usage occurs in another place which refers to Abram,

Jehovah brought him outside and said, Look up now towards heaven, and count the stars, if you are able to count them. And He said to him, So will your seed be. Genesis 15:5.

Here in like manner, because Abram represented love, which was saving faith, no other descendants are meant in the internal sense by 'his seed' but all people throughout the world who dwell in love.

[5] Similarly,

I will establish My covenant between Me and you and your seed after you. And I will give to you, and to your seed after you, the land of your sojournings, all the land of Canaan, for an eternal possession; and I will be their God. This is My covenant, which you shall keep between Me and you and your seed after you: every male among you shall be circumcised. Genesis 17:7-8, 10.

Here too 'establishing a covenant' means the conjunction of the Lord with men throughout the world by means of love, a love represented by Abram. From this it is clear what his seed means, namely all people throughout the world who dwell in love. The covenant involved the circumcision mentioned here. By this heaven never understands circumcision of the flesh but circumcision of the heart - the circumcision received by people who dwell in love. Circumcision was a representative of regeneration by means of love, as is explained clearly in Moses,

Jehovah God will circumcise your heart, and the heart of your seed, so that you will love Jehovah your God with all your heart and with all your soul, that you may live. Deuteronomy 30:6.

From these words it is clear what circumcision is in the internal sense. Consequently wherever circumcision is mentioned it is used to mean nothing other than love and charity, and the life deriving from these.

[6] That 'the seed of Abraham' means all people throughout the world who have love is also clear from the Lord's words to Abraham and to Isaac - to Abraham after he had shown his willingness to sacrifice Isaac as commanded,

I will certainly bless you and I will certainly multiply your seed as the stars of heaven and as the sand which is on the seashore. And your seed will inherit the gate of your enemies, and in your seed all the nations of the earth will be blessed. Genesis 22:17-18.

Here it is quite clear that 'seed' is used to mean all people throughout the world who have love.

[7] Just as Abraham represented celestial love, as has been stated, so Isaac represented spiritual love; consequently 'the seed of Isaac' means nothing else than all with whom spiritual love, or charity, resides. Of them the following is said,

Sojourn in this land and I will be with you and will bless you, for to you and to your seed I will give all these lands, and I will fulfil the oath which I swore to Abraham your father, and I will cause your seed to multiply as the stars of heaven, and I will give to your seed all these lands, and in your seed all the nations of the earth will be blessed. Genesis 26:3-4, 24.

This clearly means all nations who dwell in charity. Celestial love was represented by Abraham as 'the father' of spiritual love represented by Isaac, for what is spiritual is born from what is celestial, as shown already.

[8] Since Jacob represented the external features of the Church which arise from those that are internal, and so represented all things in the external man that have their origins in love and charity, 'his seed' therefore means all people throughout the world whose worship is external containing internal worship, and whose charitable acts contain charity from the Lord. Concerning that seed Jacob was told, after he had seen the stairway in a dream,

I am Jehovah, the God of Abraham your father, and the God of Isaac. The land on which you are lying I will give to you and to your seed, and your seed will be as the dust of the earth. And in you, and in your seed, will all the families of the ground be blessed. Genesis 18:13-14; 32:12; 48:4.

[9] That 'seed' has no other meaning becomes clear from the following places, in addition to those quoted from the Word in 255. In Isaiah,

You, Israel, My servant, Jacob, whom I have chosen, the seed of Abraham, My friend. Isaiah 41:8.

This refers to the regeneration of man. When the distinction is made between Israel and Jacob, as it is frequently, 'Israel' means the internal spiritual Church, 'Jacob' the external features of the same Church. Both are called 'the seed of Abraham', that is, of the celestial Church, because celestial, spiritual, and natural follow one another consecutively. In Jeremiah,

I had planted you as a wholly excellent vine, a seed of truth. How have you turned from Me into the degenerate [branches] of a strange vine? Jeremiah 2:21.

This refers to the spiritual Church, which is 'an excellent vine', whose charity, that is, faith deriving from charity, is called 'a seed of truth'.

[10] the same prophet,

As the host of heaven is unnumbered, and the sand of the sea immeasurable, so I will multiply the seed of David My servant, and the Levites ministering to Me. Jeremiah 33:22.

Here 'seed' clearly stands for heavenly seed, for 'David' means the Lord. The fact that the seed of David was not like the unnumbered host of heaven, or the immeasurable sand of the sea, is well known to everyone. In the same prophet,

Behold, the days are coming, says Jehovah, and I will raise up for David a righteous branch and He will reign as King, act with understanding, and execute judgement and righteousness in the land. In His days Judah will be saved, and Israel will dwell with confidence. And this is His name which they will call Him, Jehovah our Righteousness. Therefore, behold, the days are coming, says Jehovah, and men will say no longer, As Jehovah lives who brought up the children of Israel out of the land of Egypt, but, As Jehovah lives who brought up and led the seed of the house of Israel out of the land of the north. Jeremiah 23:5-8.

Here entirely different things are meant from those that appear in the letter - David, Judah, and Israel do not mean David, Judah, and Israel, but David means the Lord, Judah that which is celestial, and Israel that which is spiritual. Consequently 'the seed of Israel' means people who have charity, that is, faith inhering in charity.

[11] In David,

You who fear Jehovah, praise Him! all the seed of Jacob, glorify Him! stand in awe of Him, all the seed of Israel! Psalms 22:23-24.

Here 'seed of Israel' is used to mean no other seed than the spiritual Church. In Isaiah,

Its stump will be the holy seed. Isaiah 6:13.

'Holy seed' stands for remnants, which are holy because they are the Lord's. In the same prophet,

I will bring forth seed from Jacob, and from Judah the possessor of My mountains, and My chosen ones will possess it, and My servants will dwell there. Isaiah 65:9.

This refers to the celestial Church, external and internal. In the same prophet,

They will not generate in sudden terror. They will be the seed of the blessed of Jehovah, and their offspring with them. Isaiah 65:23.

This refers to the new heavens and a new earth, that is, to the Lord's kingdom. People who are there, having been generated, or regenerated, from love, are called 'the seed of the blessed of Jehovah'.