[separate|sort out] the sheep from the goats

to distinguish the good from the bad

The idiom "separate the sheep from the goats" has its roots in biblical and agricultural references. The phrase comes from the Gospel of Matthew in the Bible, where it is used metaphorically to describe the act of distinguishing or separating the righteous (symbolized by sheep) from the unrighteous or inferior (symbolized by goats). Figuratively, it is used to refer to the differentiate between two groups or individuals based on their qualities, characteristics, or merits.

The coach needs to separate the sheep from the goats during tryouts to form the best team.
It's important to sort out the sheep from the goats when hiring new employees to ensure we get the most qualified candidates.
The professor carefully sorted out the sheep from the goats in the class by evaluating their performance on the exam.
The judge will have to separate the sheep from the goats to determine who is responsible for the crime.
The manager had the difficult task of sorting out the sheep from the goats among the employees to identify the top performers.