Sort out/separate the sheep from the goats British American verb
Mom : How do you think about your classmates ? Son : I find it fairly hard to separate the sheep from the goats in the first encounter.
Examination is a way to sort out the sheep from the goats.
She is so naive that she can't separate the sheep from the goats.
The idiom derives from Bible. According to Biblical belief, on the Day of Judgement as well as the day the world ends, God will sort out the sheep from the goats. The sheep (symbolizes the good person) will go to heaven and the goat (embodies the bad one) will go to hell.
To decide to believe someone‘s saying although they may not tell the truth
He said that he was late because he had an accident and I gave him the benefit of the doubt.