Adams identity function (Exodus 3:19)

[timelets]

In the sweat of thy face shalt thou eat bread, till thou return unto the ground; for out of it wast thou taken; for dust thou art, and unto dust shalt thou return.'  --- Exodus 3:19

This is another classic example of specifying an identity function, this time for the man (Adam):

f: A -> B (where A is dust and B any place or state of the man on Earth);
g: B -> A (return to the state of dust).

The identity function of Adam:

1_{Adam =} g º f