'Tar and pitch,' as in Exodus 2:3, signify good mixed with evils and falsities, because 'tar' signifies good mixed with evils, and 'pitch' signifies good mixed with falsities. This significance is based on their flammable nature, and anything fiery or flammable in the Word signifies good, and in the opposite sense, evil. But because they are sulfurous and black, they signify evil and falsity. (Arcana Coelestia 6724)