"... the day of the Lord will come as a thief in the night;"
2 Peter 3:10
Partakers of the Divine Nature, 2 Peter 1
The nature of the world is entirely separate from the nature of the spirit. Throughout the Bible God requests that we be holy. Interestingly, the word holy means separate. If we are called to be separate, we must need to be different... but from what? The world. The kingdom of Heaven operates in a different manner, and for a different purpose, than the world does. As a consequence of that, the world does provide what we need to diligently develop in the nature of the spirit. The world tempts our bodies. The Lord tests our spirit.
In his second letter, Paul adjures us to be diligent. Focused. Attentive. Productive. Intentional. Involved. Conscientious. So that we may be partakers of the divine nature. So that we escape the corruption that is in the world through lust. To do this, he suggests that we steadily develop our character, consistently growing upon and adding to the righteous character, behavior, and lifestyle that we learn from the Lord.
Ultimately, Jesus taught us to retrain mindset and behavior. Because of what he taught, and how he exemplified it, we learn that we are not merely biological bodies. We have a spirit that a biological body hosts and maneuvers. The body and the spirit are nourished differently;
The body is tempted by the world in that it craves and strives doggedly for what will advance itself. The scientific theory "survival of the fittest" is also the mindset of the world. Our bodies are naturally self-centered creatures. And if our spirit has not been retrained to take the reins, so are we (self-centered). Much of what we say and do and think is to satisfy our body.
The spirit is tested (rather than tempted James 1:3) by the Lord as part of the retraining process. The Lord catalyzes our spirit to be better, to develop, to establish itself, to strengthen itself, through a series of life circumstances. The "test" element of it comes from the fact that the nature of the world, in which we are smack-dab in the middle of, is separate from the divine nature. Some examples from this from Jesus' own teaching:
The meek inherit the earth. Matthew 5:5
Incredibly, this is the exact opposite of the nature of the world, of survival of the fittest. Jesus encourages us to be gentle rather than ferocious. Yet the world has trained us that ferocity obtains what it wants.
Give and you will receive. Luke 6:38
Without faith, that sentence does not even make sense. That's how separate Jesus' approach to life is from the world. The body may not gain from giving, but the spirit does. By giving, the spirit reveals itself as a capable, functional, reliable, willing vessel through which blessing comes from the Lord into the person and thereby the world.
The least will be greatest. Luke 9:48
The diligent servant of the Lord is elevated in the kingdom. The diligent servant in the world is overlooked. Uncelebrated, or even unseen and unappreciated.
Our body is a well and our spirit is the water. Through diligent faith, the living water of God fills us up. Our biological bodies become quite inconsequential when we focus on the nourishment of our spirit. Focused on spiritual nourishment, our bodies receive what they need to be healthy and functional as they maneuver our spirits to do the work of the kingdom rather than vain wants, and unproductive things, for itself (and those things are sometimes even worse than unproductive and vain, they can be harmful and corrupt).
Perished in Corruption, 2 Peter 2
The world tempts our bodies. The world proffers what our bodies desire. History and personal experience have shown how unchecked desire has deeply ensnared and damaged countless people. Yet there is good news in two parts from the Lord. Part 1: God knows how to help the godly, the holy, those earnestly endeavoring to be separate, out of temptation. God recognizes when His child is drowning and wants to be saved, wants to retrain themselves into a different outcome. He is able to save that person... from themselves, from oppressors, from vices, fears, sorrows and addictions. Part 2: God reveres the unjust to a day of judgment. So while an earnest, though imperfect, child of God (person) may not perish in corruption, the actually unjust do.
For while the kingdom of heaven is gentle, it is divinely ordered, balanced, and mightily maintained. Jesus did not teach us to be powerless; He taught us that a meek, generous, sedulous, spirit is power... for it mines its strength directly from the all powerful God (1 John 4:4). From God flows directly into us power over not just evil but all the things the secular world cannot seem to shake: grief, fear, anxiety, pain, addiction, depression, lethargy, apathy, existential-crises.
So many of the world are, as Peter states, wells without water; clouds carried by a tempest; in the mist and midst of darkness. But in the kingdom, we are light. The living water nourishes, fills and overflows us with blessing. For us, by God's command, the tempest ceases, unable to carry us off. God is our firm foundation, our provision, the source of the light and power that makes us wholly separate from those entrenched in the way of the world.
And that is as much blessing as it is responsibility. Peter aptly glorifies God for these gifts we are given but he also warns us to be diligent with our gifts. We know better, we must do better. We have much, we must give much. The expectation for us to be separate, holy, in our character and behavior increases. Regression worldly, selfish habits is a darker, deeper blemish once we are ignorant no longer of sin.
Grow in Grace, 2 Peter 3
So, grow in grace. Make it a daily mission, a lifelong endeavor, to grow in grace... in evermore precise emulation of Jesus. It is a commitment that requires action... to be holy is to actively separate, or even extricate one's mindset from where it started. If we do not grow vigilantly in grace, we neglect to develop. Worse, we regress. We need consistent conversation with God and review and reflection of Jesus' life to remember, to maintain, to grow to be spirits God will call His own and call to action.
For we do want to be active, in earth and heaven. Even the word "angel" means messenger. That implies action and duty. We want to be participants of the operation of the kingdom of heaven, part of its many-membered-whole. We learn that diligence here, now. This life in the world is a chance for development that could progress us into service within the kingdom of God. We can be proponents of the spirit now by doing God's work here.
And because, as of right now, we cannot completely separate from our body we need to learn to rely on God. To source our needs from Him. To let Him fill the tanks within us that actually bring happiness (generosity, service, kindness). Our spirit needs power from Him to overtake the temptations of the body that bring us no peace, no joy, no fulfillment.