“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.” 2 Peter 1:4
The word of God sanctifies us from the decadence in the world, so firstly, by believing the gospel, we are born of the word of God:
“Being born again, not of corruptible seed, but of incorruptible, by the word of God, which liveth and abideth for ever.” 1 Peter 1:23
And then renewing our minds, he expects us to live by the word of God:
“And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.” Romans 12:2
In living by the word of God, and renewing your mind, you have to agree with the main verse- you have been granted exceeding great and precious promises so that you can participate fully with the divine nature that you now possess- agree with that.
Also, realize that you have escaped the decadence in the world, meaning you ought never to identify with the corruption in the world or get perturbed that you might be affected in some way by it, but insist on the picture given you by the word of God:
“Who gave himself for our sins, that he might deliver us from this present evil world, according to the will of God and our Father:” Galatians 1:4