Christ "It is finished."
If not, then all that stuff St. Paul said about "finishing the race," and "If anyone thinks he stand, let him take heed lest he fall" was kind of irrelevant blather. And Jesus had no real warning or admonition in mind for us when He said,
Matthew 10:22
But the one who endures to the end will be saved.
Matthew 24:13
But the person who endures to the end will be saved.
Mark 13:13
You will be hated by everyone because of my name. But the one who endures to the end will be saved.
In fact, all commandments, all warning, all admonitions, all encouragements to "hold fast" are a mockery, pure nonsense, if in the end our willing cooperation means nothing.