At the end of Matthew 24, for one. Such as the following.
Matthew 24:48 But and if that evil servant shall say in his heart, My lord delayeth his coming;
49 And shall begin to smite his fellowservants, and to eat and drink with the drunken;
50 The lord of that servant shall come in a day when he looketh not for him, and in an hour that he is not aware of,
51 And shall cut him asunder, and appoint him his portion with the hypocrites: there shall be weeping and gnashing of teeth.
It is silly, for instance, that an atheist, or a satanist, for example, would be saying in his heart, My lord delayeth his coming. Only a professed servant of Christ would or could be saying something like that. And look what happens to that one according to verse 51. When?
Matthew 25:30 And cast ye the unprofitable servant into outer darkness: there shall be weeping and gnashing of teeth.
31 When the Son of man shall come in his glory, and all the holy angels with him, then shall he sit upon the throne of his glory:
32 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:
33 And he shall set the sheep on his right hand, but the goats on the left.
As to Matthew 25:30, even though Jesus used another parable to describe this particular unprofitable servant of His, this is still meaning that unprofitable servants of His are meant in Matthew 24:48-51 as well, and that Jesus specifically deals and confronts them once Matthew 25:31-33 is being fulfilled.
Sometime ago I ran across a link where one poster pretty much summed up my understanding of the sheep and goats judgment, and expressed it better than I could. Here it is below.
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Goats and sheep are indistinguishable from a distance in the same way that wheat and tares are indistinguishable. Both sheep and goats are also "kosher" animals, which makes them similar. Thus this judgment is not between the righteous (believers) and wicked (unbelievers), but between the righteous (believers) and the apparent-righteous (unbelievers). In other words, the scope of this judgment is for the declared followers of the shepherd, who are ostensibly "kosher" creatures.
Ezekiel 20:33-44 appears to be the parallel account in the Hebrew Bible to this passage in Matthew, when the Lord God will one day regather his people from the nations of the world in order to be their king. That is, this regathering will be a mix of the righteous (believers) and the apparent-righteous (unbelievers). Thus he will judge his people in the "wilderness of the peoples" (Ezek 20:35). The comparison here is to the wilderness of the land of Egypt (Ezek 20:36), where the Lord had "purged" his people in order to prevent "rebels and transgressors" from entering the Promised Land. Thus the scope of judgment is limited to the declared followers of the Lord. As the shepherd he will make his people "pass under the rod" (Ezek 20:37). In this context, the goats will undergo the following.
Matthew 7:21-23 (NASB) 21 “Not everyone who says to Me, ‘Lord, Lord,’ will enter the kingdom of heaven, but he who does the will of My Father who is in heaven will enter. 22 Many will say to Me on that day, ‘Lord, Lord, did we not prophesy in Your name, and in Your name cast out demons, and in Your name perform many miracles?’ 23 And then I will declare to them, ‘I never knew you; depart from Me, you who practice lawlessness.’”
At the end of Matthew 25:31-46 the announcement is made: “These (goats) will go away into eternal punishment, but the righteous (sheep) into eternal life.” That is, the sheep are the righteous (believers) and the goats are the unrighteous (unbelievers) notwithstanding that both groups were the ostensible and therefore self-declared followers of the Lord.
The idea here is that those "believers" who love other "believers" through both their words and deeds are indeed the sheep (cf. Ja 2:15-17 and 1 Jn 3:18), whereas the remainder (the goats) are those whose spiritual gifts (which were prophesying, healing, miracles) were of no use or benefit to the sheep (hunger, thirst, nakedness, sickness, and their loneliness in incarceration) and therefore the goats were never "known" by the Lord.
Who are the Sheep and the Goats in Matthew 25?