"seeing that His divine power has granted to us everything pertaining to life and godliness, through the true knowledge of Him who called us by His own glory and excellence." (2 Peter 1:3)Peter's writing style can be a bit difficult to follow at times, but I'll give it my best "college try." Everything we have of any value begins with the knowledge of God. In Peter's day, many people claimed knowledge; scientists, philosophers, and some religious leaders, but for many, it was only knowledge of "stuff". Some of the heresies that sprung up in Peter's day also claimed to be birthed out of knowledge, a knowledge of spiritual things and spiritual hierarchies. Some even claiming knowledge and revelation that was greater than what Christ or even His Father knew, but it was only a knowledge of (supposed) facts. However, such knowledge benefits us little, in fact Paul said, "Knowledge puffs up, but love edifies." (1 Cor 8:1 NKJV) It's not enough to know about God, we must know God, and it is this knowing that releases God's power in our lives. It is through this power that we gain access to all heavenly and divine power to make provision for everything we need for living a godly life. We can try to be good on our own, but its only when we come to know God that we gain access to the power to be good, the power to live right.
"For by these He has granted to us His precious and magnificent promises, so that by them you may become partakers of the divine nature, having escaped the corruption that is in the world by lust." (2 Peter 1:4)
For by what? By His divine powers released through the knowledge of Him. His promises are backed by His power and made available to use through the knowledge of Him. God's promises are not only great, they are also precious. The Greek word for "precious" can also be translated "costly." God's precious promises can only be purchased by something of equal or greater preciousness, such as, "with the precious blood of Christ:" (1 Peter 1:19 NIV) The goal of the promises is to make us partakers, or companions with Christ, in the divine nature. However, its not the promises alone that produces the divine nature within is, but obtaining those promises. Its not enough to merely believe the promises but we must also inherit those promises. This requires faith, and a bit more. "so that you will not be sluggish, but imitators of those who through faith and patience inherit the promises." (Hebrews 6:12)
Our journey towards life, godliness, and possessing the divine nature all begins when we are born again, when we die to this world and come alive to the Kingdom of God, when we escape the kingdom of this age and arrive in the Kingdom of God's Son, "For He rescued us from the domain of darkness, and transferred us to the kingdom of His beloved Son."(Colossians 1:13) Peter refers to the corruption that is in the world due to lust. The Greek word for "corruption" represents a body decaying in the ground. This world, and the world system, is fading away, it is already dead and decaying. "for the form of this world is passing away." (1 Corinthians 7:31) We were once part of this corruption; already "dead in your transgressions and the uncircumcision of your flesh." ("Colossians 2:13) and our human nature decaying even as we lived. However, when we came to Christ, our old nature died and our new nature came to life, a nature divine in promise. This is our hope which we seek to obtain through the great and precious promises of God. To live a life that is growing and maturing towards life, not one that is decaying into death. The old life we have escaped, the new life we are reaching forward to obtain in all its fullness.