7906. 'No yeast shall be found in your houses' means no falsity whatever shall come near good. This is clear from the meaning of 'yeast' as falsity, dealt with below; and from the meaning of 'house' as good, dealt with in 3652, 3720, 4982, 7833-7835. The meaning of 'yeast' as falsity becomes clear from the places where yeast and anything made with yeast, and also where unleavened and anything made without yeast are mentioned, such as in Matthew,

Jesus said, Look out for and beware of the yeast of the Pharisees and Sadducees. Then the disciples understood that He had not said that they should beware of the yeast used in bread, but of the teaching of the Pharisees and Sadducees. Matthew 16:6, 11.

Here 'yeast' plainly stands for false teaching. Because 'yeast' meant falsity it was forbidden to sacrifice the blood of the sacrifice with anything made with yeast, Exodus 23:18; 34:25. For 'the blood of the sacrifice' meant holy truth, thus truth pure and free from all falsity, 4735, 6978, 7317, 7326, 7846, 7850. It was also laid down that the minchah offered on the altar should not be baked with yeast in it, Leviticus 6:15-17, and that cakes and wafers also should be made without yeast, Leviticus 7:11-13.

[2] To go further with what 'made with yeast' and 'not made with yeast' refer to, it should be recognized that the purification of truth from falsity cannot ever come about in a person without so called fermentation, that is, without the conflict of falsity with truth and of truth with falsity. But after the conflict has taken place and truth has triumphed, the falsity falls away like dregs and the truth emerges purified. It is like wine that becomes clear after fermentation as the dregs sink to the bottom. That fermentation or conflict takes place especially when a person's state undergoes a change, that is to say, when his actions begin to spring from the good of charity, and not as previously from the truth of faith. For a person's state is not yet made pure while his actions spring from the truth of faith, but they have been made pure when they spring from the good of charity, since they now spring from his will. Previously they sprang merely from his understanding.

[3] Spiritual conflicts or temptations are fermentations in the spiritual sense, for during them falsities wish to link themselves to truths, but the truths reject them, eventually sending them to the bottom so to speak and in that way becoming refined. This is the sense in which to understand what the Lord teaches about 'yeast' in Matthew,

The kingdom of heaven is like yeast, which a woman took and hid in three measures of flour, until the whole was fermented by it. Matthew 13:33.

'Flour' is truth from which good is derived. Also in Hosea,

They are all committing adultery, like an oven heated by a baker; the raiser ¹ ceases from kneading the dough until it has fermented. Hosea 7:4.

Since such conflicts, meant by 'fermentations', take place with a person in the state before he attains newness of life, as has been stated, it was also laid down that the new minchah, the bread of the wave-offering, that was to be brought at the feast of first fruits, should be baked with yeast; and that was to be the first fruits to Jehovah, Leviticus 23:16-17.

Footnotes:

3735. 'And clothing to wear' means being joined to Divine Truth. This is clear from the meaning of 'clothing' as truth, dealt with in 1073, 2576, Divine Truth here since the Lord is the subject; and from the meaning of 'wearing' as making it one's own and being joined to it. As for the nature of the internal sense of the Word, that becomes clear from these and all other details; that is to say, when the sense of the letter refers to bread and to clothing, and also when it does so within historical narrative, as here in 'If God will give me bread to eat and clothing to wear', the angels present with a person at the time have no thought at all of bread but of the good of love, and in the highest sense, of the Lord's Divine Good. Nor do they have any thought at all of clothing but of truth, and in the highest sense, of the Lord's Divine Truth. To them such things as are referred to in the sense of the letter are simply objects for thought regarding heavenly and Divine matters, for such things are vessels existing in the ultimate degree of order.

[2] So when with holiness of mind a person thinks about bread - for example, when he thinks about the bread in the Holy Supper, or about the daily bread in the Lord's Prayer - that thought which he has about bread serves the angels present with him as an object for thought regarding the good of love which comes from the Lord. For the angels do not take hold of anything at all of the person's actual thought concerning bread, but instead their thought concerns good; for such is the correspondence between the two. It is similar when with holiness of mind a person thinks about clothing. The angels' thought in that case concerns truth. So it is with everything else in the Word. From this the nature of the joining together of heaven and earth by means of the Word becomes clear; that is to say, the joining together is such that when with holiness of mind anyone reads the Word he is joined by means of such correspondences more closely to heaven, and through heaven to the Lord, even though that person's thought is concerned solely with things in the Word which are stated in the sense of the letter. His holiness of mind at that time is the product of the influx of celestial and spiritual thoughts and affections such as exist with angels.

[3] So that such influx might exist and from that influx man might be joined to the Lord, the Lord has instituted the Holy Supper where it is explicitly stated that the Lord is the bread and wine. For the Lord's body means His Divine love, and the reciprocal love in man, love such as exists with celestial angels, while His blood in a similar way means His Divine love, and the reciprocal love in man, but love such as exists with spiritual angels. From this it is evident how much of the Divine there is within every individual part of the Word, though man does not know what that Divine content is or the nature of it. People however who, while in the world, have led a good life enter after death into cognitions and a perception of all those things, for at that time they cast off earthly and worldly things and take to themselves heavenly ones, and have, like angels, spiritual and celestial ideas.