Who said "I must focus on the task at hand."?

This quote is attributed to Dexter.

I must focus on the task at hand. - Dexter

"I must focus on the task at hand."

Dexter Work

"What does this button do?"

"I must focus on my work."

"Science rules!"

"Dee Dee, get out of my laboratory!"

"Hard work never killed anybody."

"Work with purpose and integrity."

"Hard work pays off in the end."

"A man's gotta do what a man's gotta do."