The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish but that all should come to repentance. (2 Pet. 3:9, NKJV)This is one of those verses that, taken in isolation, are used to attack Calvinism. After all, it seems to state plainly enough that the Lord is not willing that any should parish but that all should come to repentance.
First of all, like many verses used against Calvinism, the plain reading really supports Universalism, not Arminianism. After all, if the Lord truly wills, in the sense of His decretive will, that all, meaning every single person on earth, should come to repentance, then it would happen as surely as the cosmos were spoken into existence.
No, what we need to do is examine, from the context, just who the "all" refers to in this verse.
Part of the answer is found in the epistle's salutation:
1 Simon Peter, a bondservant and apostle of Jesus Christ, To those who have obtained like precious faith with us by the righteousness of our God and Savior Jesus Christ:
2Grace and peace be multiplied to you in the knowledge of God and of Jesus our Lord, 3 as His divine power has given to us all things that pertain to life and godliness, through the knowledge of Him who called us by glory and virtue, 4 by which have been given to us exceedingly great and precious promises, that through these you may be partakers of the divine nature, having escaped the corruption that is in the world through lust. (2 Pet. 1:1-4, NKJV)
And a bit later:
For this reason I will not be negligent to remind you always of these things, though you know and are established in the present truth. (2 Pet. 1:12, NKJV)
We see that the letter is written to believers. If you read the whole of 2 Peter there is no indication that his audience changes at any point in the epistle. That brings us to Chapter 3. Look at the "troublesome" verse in context:
1 Beloved, I now write to you this second epistle (in both of which I stir up your pure minds by way of reminder), 2that you may be mindful of the words which were spoken before by the holy prophets, and of the commandment of us,the apostles of the Lord and Savior, 3knowing this first: that scoffers will come in the last days, walking according to their own lusts, 4and saying, "Where is the promise of His coming? For since the fathers fell asleep, all things continue as they were from the beginning of creation." 5For this they willfully forget: that by the word of God the heavens were of old, and the earth standing out of water and in the water, 6by which the world that then existed perished, being flooded with water. 7But the heavens and the earth which are now preserved by the same word, are reserved for fire until the day of judgment and perdition of ungodly men.
8But, beloved, do not forget this one thing, that with the Lord one day is as a thousand years, and a thousand years as one day. 9The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us,[not willing that any should perish but that all should come to repentance.
10 But the day of the Lord will come as a thief in the night, in which the heavens will pass away with a great noise, and the elements will melt with fervent heat; both the earth and the works that are in it will be burned up. 11Therefore, since all these things will be dissolved, what manner of persons ought you to be in holy conduct and godliness, 12looking for and hastening the coming of the day of God, because of which the heavens will be dissolved, being on fire, and the elements will melt with fervent heat? 13Nevertheless we, according to His promise, look for new heavens and a new earth in which righteousness dwells.
14 Therefore, beloved, looking forward to these things, be diligent to be found by Him in peace, without spot and blameless; (2 Pet. 3:1-14, NKJV)
Again, this passage begins with Peter referring to his audience as beloved. This letter is not to the "general public”" but to those who claim to be believers. This is further emphasized by referring to the scoffers as "they"—there is a clear delineation here between "us" and "them".
Most importantly, this passage is not about salvation, but rather about believers being ever vigilant to walk-the-walk in anticipation of the Second Coming. Furthermore, Peter states that time has a different reality for God, but that in any case He will come "as a thief in the night".
Now, to the verse in question:
The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish but that all should come to repentance. (2 Pet. 3:9, NKJV)
Given the context we have established, the "us" and the "all" can be understood not to refer to all of mankind. To whom then? To believers, yes, but they are in some sense already "ready" and in no danger of perishing. What the Lord must be longsuffering about is the wait for the unsaved elect, including those not yet born, to come to repentance. What Peter is essentially saying is that God will have all those whom He has set aside, not willing to sacrifice any for the sake of expediency. He will wait until they all come to repentance, but since that may be completed at any moment (we are, of course, clueless) we should endeavor to live a holy and blameless life.