"One indeed is the universal Church of the faithful, outside which no one at all is saved, in which the priest himself is the sacrifice, Jesus Christ, whose body and blood are truly contained in the sacrament of the altar under the species of bread and wine; the bread (changed) into His body by the divine power of transubstantiation, and the wine into the blood, so that to accomplish the mystery of unity we ourselves receive from His (nature) what He Himself received from ours."
--Pope Innocent III and Lateran Council IV (A.D. 1215)
It's like:
"I made this pie. I know what went into it. Look here: cherries. It's a cherry pie."
"It's not blueberry?"
"No."
"How rigid!"
"I made this pie. I know what went into it. It's a cherry pie."
"But look. These are blueberries."
"No."
"Look!!
"No!!
"How rigid."
"2 + 2 = 4. 2 + 2 is ALWAYS 4."
"Not 6?"
"No. I'm entitled to be quite rigid about that."