For something to be cast down or cast out generally refers to a rather dramatic move from a higher spiritual state to a lower one. In most cases it's used in reference to evil desires or false thinking – or people spreading desires and false thinking – being removed and banished, even condemned to hell. Some uses are more moderate, though, and sometimes – when Moses casts down his rod in performing a miracle, for example – it signifies the sudden inflowing of the divine into the natural world.

(Odkazy: Apocalypse Explained 497, 1175; Apocalypse Revealed 252, 552, 835, 872; Arcana Coelestia 2657, 6693, 6948; The Apocalypse Explained 1181)

2657. 'Cast out this servant-girl, and her son' means that what belonged to the merely human rational was to be banished. This is clear from the meaning of 'casting out' as banishing; from the meaning of 'servant-girl' as the affection for rational concepts and for factual knowledge, and so as the good belonging to these, dealt with in 2567; and from the meaning of 'son' as the truth belonging to that rational, dealt with in 264, 489, 533, 1147. But it is apparent good and apparent truth that go with this first or merely human rational. Consequently 'cast out this servant-girl, and her son' means that to be banished were the things belonging to the merely human rational. This particular circumstance - that the first rational was banished once the Divine Rational took its place - has been stated and shown in several places already, but as it is the specific subject here, a further brief explanation is necessary.

[2] With everyone who is being regenerated there are two rationals, the first existing before regeneration, the second after. The first, which exists before regeneration, is acquired by means of the experiences of the senses, by means of reflecting on the things that take place in public life and in private life, by means of formulated knowledge, and by means of reasonings based on and presented through these, as well as by means of cognitions of spiritual things obtained from the doctrine of faith, that is, from the Word. But none of these acquisitions rise at this time very much above the ideas present in the external or bodily memory, which are relatively speaking quite materialistic. Consequently whatever thought takes place in the rational at this time consists of such materialistic ideas, or else, so that what it thinks may be comprehended at the same time by inner or intellectual sight, the semblances of such things are presented in the form of comparisons or analogies. Of such a nature is the first rational, or the rational that exists before regeneration.

[3] But the rational after regeneration is formed by the Lord by means of affections for spiritual truth and good, which affections the Lord implants in a remarkable manner within the truths of the first rational, and in this way the things there that are in agreement and are favourably disposed towards them are given life. The rest however, having no use, are separated from these, until at length spiritual goods and truths are gathered so to speak into bundles, once those that do not agree and which cannot be given life are cast away so to speak to the circumference, this being effected gradually as spiritual goods and truths increase together with the life of the affections for them. From this it is evident what the second rational is like.

[4] These matters may be illustrated by comparing them to the fruit of trees. To begin with the first rational is like unripe fruit which ripens gradually until it produces seeds within itself. Then, having reached the point when it is ready to part from the tree, its state is complete, regarding which see above in 2636. The second rational however, which the Lord confers on those who are being regenerated, is like this same fruit now lying in good soil, where the flesh surrounding the seeds decays and these express themselves from the core, after which they send down a root and also a shoot up above the ground that grows into a new tree and spreads out, till finally it produces new fruits, and after that gardens and orchards, according to the affections for good and truth which it is receiving; see Matthew 13:31-32; John 12:24.

[5] But since examples help to make things clear, take the proprium which a person has before regeneration and the proprium which he has after regeneration. From the first rational which he acquires through the means mentioned above, a person believes that it is from what there is within himself, thus from his proprium, that he thinks what is true and does what it good. This first rational is incapable of thinking anything else even when the person is taught that every good of love, and every truth of faith, derives from the Lord. But when he is undergoing regeneration, which takes place in adult years, he then starts - from the second rational which is conferred by the Lord - to think that good and truth do not spring from that which is within himself, that is, from his proprium, but from the Lord, though he still does what is good or thinks what is true, as if it began from within himself, see 1937, 1947. At this time the more he becomes confirmed in this the more he is guided into the light of truth concerning those matters, until he finally believes that all good and all truth come from the Lord. At this time the proprium belonging to the first rational is gradually separated and the Lord confers on that person a heavenly proprium which becomes that of the new rational.

[6] Take a further example. To begin with the only love known to the first rational is that of self and the world, and although it hears about heavenly love being altogether different it still has no conception of it. In this case when the person then does anything good the only delight he sees in doing it is that he may seem to himself to merit another's favour, or that he may be considered to be a Christian, or that he may obtain the joy of eternal life out of doing it. The second rational however which the Lord confers through regeneration begins to feel some delight in goodness and truth themselves and to be stirred by this delight, not on account of anything that is his own but on account of goodness and truth themselves. When led by this delight he spurns the thought of merit, until at length he detests it as something monstrous. This delight as it exists with him gradually increases and becomes a blessed delight, and in the next life a blissful delight, being for him heaven itself. From this it may now become clear how it is with each of the two rationals in one who is being regenerated.

[7] But it should be recognized that although a person is being regenerated, every single detail belonging to the first rational still remains with him. It is merely separated from the second rational, which the Lord effects in a miraculous fashion. The Lord however banished His own first rational completely, so that nothing of it remained, for what is merely human and what is Divine cannot exist together. Consequently He was no longer Mary's son but Jehovah as regards both Essences.