The doctrine of subsequence

[Luke]

2 Peter 1:4 Whereby are given unto us exceeding great and precious promises: that by these ye might be partakers of the divine nature, having escaped the corruption that is in the world through lust.

1. Who is this verse speaking to?
If we go back to verse one Peter there tells us that it is to those of like precious faith. Also it tells us in this verse that they babe escaped the corruption that is in the world. Therefore it is obvious from the context and from the scripture it self that it is addressed to Christians.

2. To whom were the promises given? Christians .

3. Why were they given? That by these ye MIGHT be partakers of the divine nature.

Just by simply examining each part of the scripture it is obvious that there is something spoken of here beyond salvation that is offered to Christians but not to sinners.

If people are partakers of the divine nature at the point of salvation what is the purpose of the exceeding great and precious promises. Why would Peter say that by these promises those who are saved might be or are enabled to partake of the divine nature if they already had. Also why would he specifically make having escaped the corruption that is in the world (being saved) a condition to receive these promises if we already received what the the promises offered?