To roast something is, in Biblical culinary terms, to cook it over a fire. Fire represents the Lord's infinite love for all things, so roasting food means producing the desire for what is good and actual good works from the love we feel from the Lord. This is used most often in reference to meat, particularly meat for sacrifices. It is also, however, used occasionally in reference to a drying process for grain; young David, for instance, was delivering “roasted” or “parched” grain to his brothers when he saw Goliath. This dried grain represents the desire for good that springs from a love of others; green grain represents the desire for good that comes from an understanding of what is true. This can be tricky, because many translations (including the King James Version) use “parched” for grain prepared this way, and also for people and things dried out by desert heat and wind, which has a separate meaning.

In Exodus 12:8, this signifies good which is from love, for fire signifies love. (Arcana Coelestia 7852)

In Isaiah 44:16, this signifies to operate from a filthy love. (Arcana Coelestia 7852[3])

In Exodus 12:9, this signifies to enjoy the good that comes from love, but not that which comes from the truth of faith. (Arcana Coelestia 7857)

4500. And came upon the city boldly, and slew every male. That this signifies that they extirpated the truths of doctrine of the Church among the Ancients, is evident from the signification of a “city,” as being the doctrine of the church (n. 402, 2449, 2943, 3216, 4478), here of the Church among the Ancients, because this church is represented by Hamor and Shechem, whose city it was; from the signification of “boldly,” as being with assurance, here the assurance of what is false and evil; and from the signification of a “male,” as being truth (n. 749, 2046, 4005). Hence it is evident that by “they came upon the city boldly and slew every male” is signified that from the assurance of falsity and evil they extirpated the truths of doctrine of the Church among the Ancients. It was the Church among the Ancients (that came from the Most Ancient Church) which would have been set up with the posterity of Jacob, because the Ancient Church had begun to perish; but it is here described in the internal sense that they extinguished in themselves all the truth of faith and good of charity, thus all the internal of worship, and that therefore no church could be instituted with that posterity; from which it came to pass that because they stubbornly insisted, the mere representative of a church was instituted with them (see n. 4281, 4288-4290, 4293, 4307, 4314, 4316-4317, 4429, 4433, 4444).