249. That to "eat dust all the days of its life" signifies that their sensuous part became such that it could not live from anything except that which is of the body and the earth, that is to say, that it became infernal, is evident also from the signification of "dust" in the Word; as in Micah:
Feed thy people as in the days of eternity. The nations shall see and shall blush at all their might; they shall lick the dust like a serpent, they shall be shaken out of their holds like creeping things [serpentes] of the earth (Micah 7:14, 16-17).
"The "days of eternity" mean the Most Ancient Church; the "nations" those who trust in their Own, of whom it is predicated that "they shall lick the dust like a serpent."
In David:
Barbarians shall bow themselves before God, and His enemies shall lick the dust (Ps. 72:9).
"Barbarians" and "enemies" are those who regard only earthly and worldly things. In Isaiah:
Dust shall be the serpent's bread (Isa. 65:25).
As "dust" signifies those who do not regard spiritual and celestial things, but only what is corporeal and earthly, therefore the Lord enjoined His disciples that if the city or house into which they entered was not worthy, they should "shake off the dust of their feet" (Matt. 10:14). (That "dust" signifies what is condemned and infernal, will be further shown at verse 19.)