9298. 'You shall not sacrifice the blood of My sacrifice with anything made with yeast' means that worship of the Lord arising from the Church's truths must not be mingled together with falsities arising from evil. This is clear from the meaning of 'sacrificing' and 'sacrifice' as worship of the Lord, dealt with in Arcana Coelestia 922, 923, 2180, 2805, 2807, 2830, 3519, 6905, 8680, 8936; from the meaning of 'something made with yeast' as something falsified and falsity arising from evil, dealt with in Arcana Coelestia 2342, 7906, 8051, 8058; and from the meaning of 'blood' as truth derived from good, thus the Church's truth, dealt with in Arcana Coelestia 4735, 6978, 7317, 7326, 7846, 7850, 7877, 9127. From these meanings it is evident that 'you shall not sacrifice the blood of My sacrifice with anything made with yeast' means that worship of the Lord arising from the Church's truths must not be mingled together with falsities arising from evil. What falsity arising from evil and falsity not arising from evil are, see Arcana Coelestia 1679, 2408, 4729, 6359, 7272, 8298, 9258.
Arcana Coelestia 922-923)
 The reason why truths derived from good, which are the Church's truths, must not be mingled together with falsities arising from evil is that they are in total disagreement. They are opposites, which causes them to clash, as a result of which either good perishes or evil is put to flight; for good comes from heaven, that is, from the Lord by way of heaven, and evil from hell. Truths may, it is true, exist with the evil, and also falsities with the good; but truths present with the evil are not mingled together with falsities arising from evil present with them as long as they reside solely in the memory, serving as the means to evil. As long as this is so the truths are devoid of life. But if the truths are falsified to lend support to evil, which is also brought about by perverse interpretation, they are mingled together. This leads to the profanation of truth, the nature of which, see Arcana Coelestia 1008, 1010, 1059, 1327, 1328, 2051, 2426, 3398, 3399, 3402, 3489, 4601, 6348, 6595, 6959, 6963, 6971, 8394, 8943, 9188.
Arcana Coelestia 1327-1328, 3398-3399, 4289, 6959-6960)
 The fact that accompanying a sacrifice with something made with yeast was forbidden is evident from the following law regarding a minchah, which was burned on the altar together with a sacrifice, the words of that law in Moses being,
Every minchah which you bring to Jehovah shall be made without yeast; no yeast nor any honey shall be used along with the fire-offering you burn to Jehovah. Leviticus 2:11.
From all that has been said it is clear that the profanation of truth is meant by this law. It also explains why the words 'the blood of [My] sacrifice' are used and not simply 'the sacrifice'; for 'the blood' is truth derived from good.
Exodus 23:18; Leviticus 2:2)