Here is Calvin's response:

Not willing that any should perish. "So wonderful is his love towards mankind, that he would have them all to be saved, and is of his own self prepared to bestow salvation on the lost. But the order is to be noticed, that God is ready to receive all to repentance, so that none may perish; for in these words the way and manner of obtaining salvation is pointed out. Every one of us, therefore, who is desirous of salvation, must learn to enter in by this way.

But it may be asked, If God wishes none to perish, why is it that so many do perish? To this my answer is, that no mention is here made of the hidden purpose of God, according to which the reprobate are doomed to their own ruin, but only of his will as made known to us in the gospel. For God there stretches forth his hand without a difference to all, but lays hold only of those, to lead them to himself, whom he has chosen before the foundation of the world."

(Edwards again) In this particular verse Peter is not speaking of the hidden purposes (His unseen will) of God, only the general call of the gospel to all people to come for life in Jesus Christ.

Ultimately we end up with what J. I. describes as an "antimony" which is a contradiction between two laws that are both true. We have sovereignty on the one hand and human responsibility on the other......both of which are true, yet they do not make sense to our finite minds. The answer according to Packer (and I agree) is that how can humans with puny brains understand everything there is to know about an infinite God.

In other words both are true and we don't know why! It's like praying for someones salvation and having them receive Christ. Did they choose for themselves?.....yes. Did prayer play a part in it?.....yes. Did God's Holy Spirit convict them and lead them to the Savior?......yes? Was in human responsibility or God's sovereignty that came into play?.....yes!

If you want everything rolled up into a neat little package that you can understand, all you end up with is a god of your own making. If you know the infinite Almighty that does what He wants, whenever He wants and no one can stop Him (the God of scripture) then there will be mysteries.