In a previous post, I discussed the common LDS interpretation of John 10:16, as well as provided a counter to the claim that the "other sheep" Christ spoke about were the Gentiles. I just came across this discussion on this text from a Protestant apologist which adds further information against the Gentile interpretation of this verse:
There are two major problems with this interpretation. First of all, if men are sheep before they believe then they already have eternal life: “And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand” (John 10:28). If the sheep were never goats then how can they be born “dead in trespasses and sins” (Eph. 2:1)? No one among the unsaved Gentiles is ever called sheep. Try pigs and dogs (Mat. 7:6; 15:26-27; 2 Pet. 2:1, 22). The Gentiles were “without Christ, being aliens from the commonwealth of Israel, and strangers from the covenants of promise, having no hope and without God in the world” (Eph. 2:12). Can one of God's sheep go to hell? Why then must God's sheep believe on Christ?
The second problem concerns the identification of the sheep. Who are the sheep? According to Micaiah (1 Kgs. 22:17), Asaph (Psa. 74:1; 78:52; 79:13), the Psalmist (Psa. 44:11, 22; 95:7; 100:3), David (Psa. 119:176), Isaiah (Isa. 53:6), Jeremiah (Jer 23:1; 50:6, 17), Ezekiel (Eze. 34:6, 11, 12), and Jesus Christ (Mat. 10:6: 15:24): the sheep are Israel. Notice the condition of Israel in the Old Testament:
My people hath been lost sheep: their shepherds have caused them to go astray, they have turned them away on the mountains: they have gone from mountain to hill, they have forgotten their restingplace (Jer. 50:6) Mu sheep wandered through all the mountains, and upon every hill: yea, my floc, was scattered upon all the face of the earth, and none did search or seek after them (Eze. 34:6). Then notice a forgotten prophecy from the Lord:
For thus saith the Lord GOD; Behold, I, even I, will both search my sheep, and seek them out. As a shepherd seeketh out his flock in the day that he is among his sheep that are scattered; so will I seek out my sheep, and will deliver them out of all places where they have been scattered in the cloudy and dark day. And I will bring them out from the people, and gather them from the countries, and will bring them to their own land, and feed them upon the mountains of Israel by the rivers, and in all the inhabited places of the country. I will feed them in a good pasture, and upon the high mountains of Israel shall their fold be: there shall they lie in a good fold, and in a fat pasture shall they feed upon the mountains of Israel. I will feed my flock, and I will cause them to lie down, saith the Lord GOD. I will seek that which was lost, and bring again that which was driven away, and will bind up that which was broken, and will strengthen that which was sick: but I will destroy the fat and the 1 strong; I will feed them with judgment. (Eze 34:11-16) Note also the New Testament counterparts:
But go rather to the lost sheep of the house of Israel (Mat. 10:6) But he answered and said, I am not sent but unto the lost sheep of the house of Israel (Mat. 15:24) When Christ came, his sheep—like Simeon (Luke 2:25), Annas (Luke 2:36-38), Zacharias and Elisabeth (Luke 2:8-20), and the disciples (John 1:40-49)--knew him (John 10:14), followed him (John 10:27), and received eternal life (John 10:28). We have here the separation of the Jewish sheep from the goats and the drawing of them to the Messiah.
Laurence M. Vance, The Other Side of Calvinism Rev. Ed. (Vance Publications, 1999), 339-40.