"His divine power has granted to us all things that pertain to life and godliness, through the knowledge of him who called us by his own glory and excellence, by which he has granted to us his precious and very great promises, so that through them you may become partakers of the divine nature, having escaped from the corruption that is in the world because of sinful desire." -- 2 Peter 1:3-4
What does Peter mean when he says that we may become partakers, or sharers, of the divine nature? Many theologians are quick to note (rightly) what he does not mean: Peter does not mean that we will be merged with the divine essence, losing our personal identities as we are ontologically one with God. That teaching would stand at odds with the whole teaching of Scripture regarding God's transcendence, supremacy, and sovereignty over us. It would eliminate our ability to worship God forever, because worship requires that lesser beings respond in awe and gratitude to a greater Being.
But if that is not what is meant, what does that strange phrase mean? I think Protestants have a tendency to interpret the phrase in a moral, as opposed to an ontological, sense. That is to say, sharing in the divine nature means, on this view, that we are conformed morally to God's character. Protestant interpreters would point to the modifying phrase "having escaped from the corruption that is in the world because of sinful desire"to bolster this claim.
While I agree that moral transformation is key to what Peter is speaking of here, I think we need to leave room for ontological transformation as well. That is to say, Peter is speaking not only of our conformity to God's character, but also of the transformation of our being into a fitness for a different realm of existence, namely, Heaven. In short, Peter speaks of our glorification.
It seems best to understand our escape from the corruption that is in the world as an escape from the physical corruption of this present age. This world is under God's curse and is, therefore, subject to death, decay, and ultimate destruction. We who are in Christ will escape that coming destruction (which is the result of humanity's sinful desire, which resulted in the curse) and inherit instead the life of the world to come. We will join the heavenly assembly in a world that is incorruptible, undefiled, and unfading (1 Pet. 1:3-4) when this present world gives way to a new creation.
Sharing in the divine nature means sharing in the glory of the heavenly realm, escaping this present evil age destined for destruction. This is the glorious future promised to all who are in Christ.