1 Corinthians 10:12

Wherefore let him that thinketh he standeth take heed lest he fall. [The weaknesses of saints in former days, notwithstanding their privileges, should warn us of our own frailty lest we presume to dally with temptation, and so fall. This verse is a stumbling-block to those who hold the doctrine "once in grace, always in grace." Whedon aptly says of the Israelites: "If they never truly stood, they never fell; and if they fell, they once stood. If their fault and ruin was in actually falling, then their salvation would have been in actually standing--standing just as they were." Their history does not show the mere possibility of apostasy, but demonstrates its actual reality, and the sad prevalence of it. But the apostle, well aware that so weighty and forceful an argument would breed a spirit of hopelessness and despair in the breasts of the Corinthians, now sets himself to show that the temptations so fatal to Israel need not prove similarly disastrous to them if they were not presumptuous, but looked to God to aid them in escaping such temptations.]