God sent Jeremiah down to the potters house to observe the potter throwing a pot, that is, creating a vessel.  A potter first chooses the clay as God chooses us. He adds water to soften the clay and kneads it as a woman would with dough.  The water represents the Word of God.  The clay is then placed in the center of the potter's wheel which represents the circumstances surrounding our lives. As he begins to turns the wheel, he begins to skillfully shape the vessel using his hands to press against the clay. He continually to adds water along the way to keep the vessel pliable.  He puts either his thumb or forefingers into the vessel applying pressure between the two to form the shape of the vessel. 
 
 If he finds a lump in the clay, he crushes the vessel with his hands, adds more water, and again kneads the clay until it becomes pliable.  He places the clay back on the wheel and starts over reshaping the vessel. The potter may also take a sharp tool to etch special designs into his pot. 

 God, as the potter, has a design in mind for us.  He often places us into the middle of our circumstance, adds the water of the Word, kneads us and begins to shape us through the pressure of His hands. If He finds a hard lump, He does not throw us away, but crushes us, adds more of the Word and starts over again.