The modern version of "The proof is in the pudding." Implies that there is a lot of evidence that I will not go through at this moment and you should take my word for it, or you could go through all of the evidence yourself.
Carpenter: The lumber for the framing of the house requires all the boards to be the same length; the proof is in the pudding.
The original saying is "the proof of the pudding is in the eating", basically meaning that something has to be experienced/utilized in order to prove how good it is.
This phrase got messed up by idiots who don't quite understand what they are saying.
Similar mistakes include could care less (couldn't care less), stop running around with your chicken cut off (stop running around like a chicken with its head cut off), begs the question (raises the question), here here (hear hear), and all that glitters is gold (all that glitters/glisters is not gold - "glisters" is used in the original Shakespeare quote)
PROGRESSIVE: Whatever you say, dumbass.
Tom Brady: "The proof is in the pudding"
(Tom Brady is hated by many sports fans, but the proof of his ability is shown in his constant victories and numerous records)
person 2: Isn't her mom the one that had a threesome with the mail men?
person 1: Well the proof is in the pudding