Scot McKnight gives his take on these controversial passages:
Both Calvinists and Arminians agree on this point: each person needs to persevere. The oddest thing has happened in American Evangelicalism: it has taught, whether aloud or not, the idea of "once saved, always saved" as if perseverance were not needed.
In other words, it has taught that if a person has crossed the threshold by "receiving Christ" but then decides to abandon living for Christ, that person is eternally secure. This is rubbish theology. Perseverance is an indicator of what faith is all about: a relationship that continues, that is marked by steady love. No one equates marriage with a wedding day statement of intent, and no one should equate faithfulness with a decision.
You can read Scot's entire post, here.