2 Peter 3:9 "The Lord is not slack concerning his promise, as some men count slackness; but is longsuffering to us-ward, not willing that any should perish, but that all should come to repentance."

The claimed problem for Calvinists—if God desires everyone to be saved, then how would that ever work with unconditional election?

Some would say (ie. John MacArthur) that this is God's will of desire, he desires that everyone would be saved, but that it is not his decreed will. I don't agree with this position here (as I don't believe it can be found in the context) and as God does NOT desire that everyone would be saved (Romans 9:22). God reveals Himself for His own glory, He reveals that He is loving, merciful and gracious through salvation, but He also is a just God and a God of wrath. If everyone was saved, then those attributes of God would not be known, God would not be revealing His full glory.

Having said that, let's go to the text. I won't put the entire text here, but please open up 2 Peter 3 as I go through it (reading 2 Peter 3:1-10 gives enough of the context). First, this letter is written to believers (2 Peter 1:1), and chapter 3 opens with Peter's address to the 'beloved' (2 Peter 3:3). So, if we follow the pronouns, the 'you' and 'ye' are referring to the 'beloved', the believers. In verse 3 Peter introduces the 'scoffers' or mockers—those who doubt the promise of God and His coming. These mockers are the 'they' in verse 5. These mockers are saying 'Where is the Lord? Things are the same now as they've always been.'  They are mocking the promise of Christ and that He would return.

In verse 8, Peter addresses the 'beloved' again and reminds them that time is not an issue for God, and in verse 9 tells us that he is not being slack, but longsuffering to us. He is being patient. Why is He being patient? Because He is "not willing that any should perish, but that all should come to repentance."

Now in verse 10, Peter continues to talk about the Lord's coming. In fact the entire context is about the Lord's coming, not salvation. In light of this, when Peter says that God is not willing that any should perish, but that all should come to repentance, first he is addressing the 'beloved' and second, he is talking about the Lord's coming.

God is patient towards those who haven't yet believed on Him, He is waiting for His elect to come, not willing that any should perish. That is why he tarries and is patient regarding His coming. As soon as the last of the elect come to Him, then the Lord will return.

If the Lord returned 5 years ago, those saved in the last 5 years would have perished. Instead God is patient towards us, not willing that any should perish.

It's completely consistent with Revelation 6:9-11 when those martyred for the word of God ask 'Why don't you judge and avenge us?' and the Lord told them "rest yet for a little season, until their fellow servants also and their brethren, that should be killed as they were, should be fulfilled." They asked the same question... why do you tarry Lord? Because he is waiting, not willing that any should perish but that all would come to repentance.

If we take the Arminian/Synergist view point and we read 'any' and 'all' as every single person, then God is waiting because he doesn't want a single person to perish, but wants every single person to repent. If this is the case, Christ would never return.