Who said "Mercy is a concept for the finite."?

This quote is attributed to Doomsday.

Mercy is a concept for the finite. - Doomsday

"Mercy is a concept for the finite."

Doomsday Justice

"I am the thing that darkness fears."

"Destruction is the only truth I know."

"You cannot stop what has already begun."

"I grow stronger with every battle."

"Justice must always prevail."

"You think I'm just some animal?"

"Fighting for what's right never gets easier."

"Justice is worth fighting for."