'An oven,' as in Malachi 4:1, signifies hell, where the people live who confirm themselves in false doctrines and evils of life from earthly and bodily loves.

In Exodus 7:3, this signifies exterior goods, which are natural, and are commonly called 'pleasant.'

(Odkazy: Apocalypse Explained 540)

9992. 'And unleavened bread' means purification of what is celestial in the inmost part of a person. This is clear from the meaning of 'bread' as that which is celestial, dealt with in 2165, 2177, 3478, 9545; and from the meaning of what is 'unleavened' as what has been purified, dealt with below. The inmost part of a person is meant because what is celestial consists in the good of love, and the good of love is inmost. There are three degrees in a person that follow one another in order; and these three are called celestial, spiritual, and natural. The celestial degree is the good of love to the Lord, the spiritual is the good of charity towards the neighbour, and the natural descending from this is the good of faith, which, since it descends from the spiritual, is called spiritual-natural. The situation with a person resembles that in the heavens. The inmost heaven, also called the third heaven, is where the celestial degree is situated; the second or middle heaven is where the spiritual degree does so; and the first or lowest heaven is where the natural descending from the spiritual, or the spiritual-natural degree, does so. The reason why the situation with a person resembles that in the heavens is that a person in whom good is present is heaven in the smallest form it takes, see the places referred to in 9279. The celestial heaven or kingdom and the division of this too into three will be spoken of in what follows next where cakes and wafers made from fine wheat flour are the subject.

[2] 'Unleavened' means what has been purified because 'yeast' means falsity arising from evil, 2342, 7906, so that 'unleavened' or made without yeast means pure or free from that falsity. 'Yeast' means falsity arising from evil because such falsity defiles good, and truth as well, and also because it gives rise to conflict; for when that falsity gets near good, agitation occurs, and when it gets near truth, a collision takes place. All this explains why a minchah consisting of unleavened bread was included in burnt offerings and sacrifices. Therefore it was decreed that every minchah which they brought to Jehovah should be made without yeast, Leviticus 2:11; that they should not sacrifice the blood of a sacrifice with anything made with yeast, Exodus 23:18; and that during the feast of Passover they should not eat anything made with yeast, and that anyone eating it should be cut off from Israel, Exodus 12:15, 18-20. The reason why anyone who ate anything made with yeast during the feast of Passover should be cut off from Israel was that the feast of Passover was a sign of deliverance from damnation, and in particular of deliverance from falsities arising from evil, accomplished with those who allow themselves to be regenerated by the Lord, see 7093, 9286-9292. This also explains why it was called the feast of unleavened bread.