Challenging God?

A good joke for those who wanna convert atheists but failed:

God is sitting in Heaven when a scientist says to him,

Lord, we don't need you anymore. Science has finally figured out a way to create life out of nothing. In other words, we can now do what you did in the 'beginning'."

"Oh, is that so? Tell me…" replies God.

"Well, " says the scientist, "we can take dirt and form it into the likeness
of You and breathe life into it, thus creating man."

"Well, that's interesting. Show Me."

So the scientist bends down to the earth and starts to mold the soil.

"Oh no, no, no…" interrupts God,

"Get your own dirt."