Consider John 10:25-30 (WEB),
25) Jesus answered them, "I told you, and you don’t believe. The works that I do in my Father’s name, these testify about me. 26) But you don’t believe, because you are not of my sheep, as I told you. 27) My sheep hear my voice, and I know them, and they follow me. 28) I give eternal life to them. They will never perish, and no one will snatch them out of my hand. 29) My Father who has given them to me is greater than all. No one is able to snatch them out of my Father’s hand. 30) I and the Father are one."
This seems to be a problematic passage for those believing that all mankind is finally saved. Here Jesus tells the unbelieving Jews that they are "not his sheep." The Lord's grave words at the Sheep and Goat judgment used in Matthew 25:31-46 suggest that there are only two categories of people in the whole world. There are sheep (of the lost and found variety) and goats. Doctrines like predestination and particular atonement teach us that goats do not become sheep, and sheep do not become goats. Sheep are the redeemed people of God, while goats are the unredeemed. So are these unbelieving Jews then goats with no hope of salvation?
Perhaps I have concluded too hastily and we need to drop back to the Calvinist understanding of the gospel.
In fact, this is one of the passages that led me to a Calvinistic understanding of the gospel in the past. The message seems clear enough, so what else could be concluded? The message seemed clear until I read Hosea 2:23.