Producing Gauss's law for E field in differential form

Gauss's law for E field in integral form:

(1)
Applying Gauss's Thm:

(2)

(3)
Considering enclosed charge in terms of volume by Eqn. 4:

(4)
gives Eqn. 5:

(5)

(6)
So,

(7)

(8)

(9)
Now, introducing D gives:

(9)

(10)