I'm a pre-mil, pre-trib guy, so to me, this passage is directed at the "nations" (Gentiles) at the end of the seven years of tribulation (that are covered in Matthew 24). The sheep are the nations that bless Israel and treat God's people (brethren) well. The goats are those nations that don't treat the brethren (Israel) well during the tribulation. Those who persecute the Jews during the tribulation will be judged instantly and sentenced to hell. Those who protect and favor Israel will be allowed to enter the 1,000 kingdom of Jesus' reign on earth.

Matthew 25:31, Matthew 25:32, Matthew 25:34 and Matthew 25:46