703. 16:14 For they are spirits of demons. This symbolically means that the lusts were lusts to falsify truths and to reason on the basis of falsities.

That demons symbolize lusts to falsify truths may be seen in no. 458 above. And because they were like frogs, the lusts were also lusts to reason on the basis of falsities, as said just above in no. 702.

702. Three unclean spirits like frogs. This symbolically means that there arose nothing but reasonings and lusts to falsify truths.

Spirits here have the same symbolism as demons, since we are shortly told that they were spirits of demons, and demons symbolize lusts to falsify truths (no. 458). The number three symbolizes all (nos. 400, 505), here nothing but. Frogs symbolize reasonings prompted by lusts, because they croak and are lascivious.

It is apparent from this that three unclean spirits like frogs symbolize nothing but reasonings and lusts to falsify truths.

Frogs here have the same symbolic meaning as the frogs in Egypt, because the destruction of the church among the Egyptians is likewise described by the miracles done, regarding which we are thus told in Exodus:

Aaron stretched out his hand over the waters of Egypt, and the frogs came up and covered the land... (Exodus 8:5-14, cf. Psalms 78:45; 105:30)

And later the frogs were removed, remaining only in the river (Exodus 8:11-13).

Frogs were produced from the waters of Egypt and remained in the river because the waters in Egypt, and especially those in the river there, symbolized doctrinal falsities on which the people based their reasoning.