All that hear the gospel, and live in the visible church, are not saved; but they only who are true members of the church invisible.[1]
… so that the word spoken by the prophet Isaiah might be fulfilled: “Lord, who has believed what he heard from us, and to whom has the arm of the Lord been revealed?” Therefore they could not believe. For again Isaiah said, “He has blinded their eyes and hardened their heart, lest they see with their eyes, and understand with their heart, and turn, and I would heal them.”Rom. 9:6
But it is not as though the word of God has failed. For not all who are descended from Israel belong to Israel… ,Rom. 11:7
What then? Israel failed to obtain what it was seeking. The elect obtained it, but the rest were hardened …Matt. 7:21
Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but the one who does the will of my Father who is in heaven… .Matt. 22:14
For many are called, but few are chosen.
Do some of the proof texts seem a little odd to you? Are you clueless as to how they apply?
They assume that the reader (learner?) already affirms a certain form of Covenant Theology, and they make sense as proof texts within that context. But unless you are already on board with that view, they will indeed seem a little out in left field.