In City of God, Book XIII, Ch. 1, Augustine wrote,
Having disposed of the very difficult questions concerning the origin of our world and the beginning of the human race, the natural order requires that we now discuss the fall of the first man (we may say of the first men), and of the origin and propagation of human death. For God had not made man like the angels, in such a condition that, even though they had sinned, they could none the more die. He had so made them, that if they discharged the obligations of obedience, an angelic immortality and a blessed eternity might ensue, without the intervention of death; but if they disobeyed, death should be visited on them with just sentence—which, too, has been spoken to in the preceding book.
Any scriptural basis for these types of conclusions?
Reply: I disagree with Augustine on many levels (Trinity, predestination, ecclesiology, etc.) and don't try to defend his theology. However, I wonder which part of this quote raises questions in your mind. That the world originated by means of divine creation and that the human race had a start is not controversial to me, and Genesis 3 details the Fall while Paul confirms this position in the NT (Romans 5:12ff; 1 Cor. 15).
Angels are possibly differentiated from men in Ps 8:4-5ff, but the Bible never predicates immortality of the angels, to my knowledge, unless someone interprets Lk 20:34-6 that way. As for human eternality upon obedience, that could be an implication from Gen 2:16-17 and the last portion of Gen. 3.