separate the sheep from the goats, to

separate the sheep from the goats

To separate the good from the bad. In this Biblical phrase, sheep represent the good and goats the bad. When you choose the students for your homeroom, don't separate the sheep from the goats and give me all the troublemakers!
See also: goat, separate, sheep
Farlex Dictionary of Idioms.

separate the sheep from the goats

Distinguish between good and bad individuals, or superior and inferior ones. For example, In a civil war where both sides commit atrocities, you can't separate the sheep from the goats . This term refers to Jesus's prophecy in the New Testament (Matthew 25:32) that the sheep (that is, the compassionate) will sit on God's right hand (and find salvation), and the goats (the hard-hearted) will sit on the left (and be sent to damnation).
See also: goat, separate, sheep
The American Heritage® Dictionary of Idioms by Christine Ammer.

separate the sheep from the goats

or

sort out the sheep from the goats

If you separate the sheep from the goats or sort out the sheep from the goats, you examine a group of things or people and decide which are good and which are bad. It is getting harder and harder to sort out the sheep from the goats among the 4,000 or so titles for children that are published every year. Testing exists to separate the sheep from the goats. Note: The Bible says that on the Day of Judgment, Jesus will divide his sheep from the goats. The sheep represent those who are going to heaven, and the goats represent those who are going to hell. (Matthew 25:32)
See also: goat, separate, sheep
Collins COBUILD Idioms Dictionary, 3rd ed.

separate the sheep from the goats

divide people or things into superior and inferior groups.
This expression alludes to the parable of the Last Judgement in Matthew 25:32–3: ‘And before him shall be gathered all nations: and he shall separate them one from another, as a shepherd divideth his sheep from the goats: and he shall set the sheep on his right hand, but the goats on the left’.
See also: goat, separate, sheep
Farlex Partner Idioms Dictionary

separate the sheep from the goats, to

To sort the good from the bad, the superior from the inferior. This term comes from the Bible, in which Jesus seems to make an analogy between sheep and goats and those who would sit at God’s right hand and left hand (Matthew 25:32). In the fourteenth century John Wycliffe was more explicit, stating, “Schepe that schal be savid schal be on hys rigt honde [sheep that shall be saved shall be on his right hand].” The term has been so used ever since.
See also: separate, sheep
The Dictionary of Clichés by Christine Ammer
See also:
  • separate the sheep from the goats
  • sort out/separate the sheep from the goats
  • it never rains but it pours
  • a curate's egg
  • curate
  • curate's egg
  • term
  • have a bad opinion of (someone or something)
  • have a good, bad, high, low, etc. opinion of somebody/something
  • be downhill all the way