I would like to examine four verses, all of which touch on the issue of perseverance. I ask that they be read prayerfully and with care.
1 Corinthians 9:26
26 Therefore I run thus: not with uncertainty. Thus I fight: not as one who beats the air. 27 But I discipline my body and bring it into subjection, lest, when I have preached to others, I myself should become disqualified.
Romans 8:12-13
12 Therefore, brethren, we are debtors—not to the flesh, to live according to the flesh. 13 For if you live according to the flesh you will die; but if by the Spirit you put to death the deeds of the body, you will live.
Philippians 3:12-14
12 Not that I have already attained, or am already perfected; but I press on, that I may lay hold of that for which Christ Jesus has also laid hold of me. 13 Brethren, I do not count myself to have apprehended; but one thing I do, forgetting those things which are behind and reaching forward to those things which are ahead, 14 I press toward the goal for the prize of the upward call of God in Christ Jesus.
Hebrews 4:11
11 Let us therefore be diligent to enter that rest, lest anyone fall according to the same example of disobedience.
Now the first verse is often explained away by claiming that it is merely talking about rewards,
not salvation. However, this argument contradicts the Calvinist notion of the perseverance of the saints. Why? Because if Saint Paul had been disqualified, it would be because he failed to keep his body in subjection and that would mean he was
overcome by sin. This reminds me of 2 Peter 2:20:
**20 For if, after they have escaped the pollutions of the world **through the knowledge of the Lord and Savior Jesus Christ, they are again entangled in them and overcome, the latter end is worse for them than the beginning.
So if perseverance is a sign of election, then 1 Corinthian 9:26 cannot be about mere rewards. If a person failed to persevere and was disqualified and did not receive the crown, does that not also mean that the person will not be saved? Compare** Matthew 10:22**
"… But he who endures to the end will be saved."
with
Revelation 2:10
Be faithful until death, and I will give you the crown of life.
and
James 1:12
12 Blessed is the man who endures temptation; for when he has been approved, he will receive the crown of life which the Lord has promised to those who love Him.
So if the crown is given to all those who persevere to the end, then does that not mean that is given to
all those who are glorified? If this is so, then
doesn’t diqualification from receiving the crown mean the same thing as disqualification from being glorified? Thus Paul can only be talking about disqualification from final salvation in 1 Corinthians 9:26. But if he were a Calvinist, would he cast such doubt on his own salvation?

It seems that Calvinists are far more certain of their own salvation than Saint Paul.
So regarding the original question of this thread, I respond with Saint Paul’s own words:
1 Corinthians 4:4-5
4For I am conscious of nothing against myself, yet I am not by this acquitted; but the one who examines me is the Lord.
5Therefore do not go on passing judgment before the time, but wait until the Lord comes who will both bring to light the things hidden in the darkness and disclose the motives of men’s hearts; and then each man’s praise will come to him from God.
God Bless,
Michael