William Burkitt on 2 Peter 3:13

Observe here, 1. What is the subject matter of the Christian's expectation, he looks for new heavens, and a new earth in which dwelleth righteousness, that is, only righteous persons, and perfectly righteous persons, where sin shall no more prevail.

Observe, 2. What is the ground and foundation of this hope in the Christian, it is the promise of God, we (according to his promise) look for new heavens and a new earth. To hope for any thing that God has not promised, is presumption. Hope is the expectation of some future good which God has promised and faith believed.

Observe, 3. How Christians should qualify and fit, make ready and prepare themselves for this joyful hour, this desirable place and state. Be diligent, that ye may be found of him in peace, without spot and blameless. Give all diligence that ye may be found at that day in a state of peace and reconciliation with God by justification, and without spot, and blameless, without any allowed spot or blame, by pressing now after the highest measures of sanctification, that so an entrance may both joyfully and abundantly be administered to you into that kingdom wherein dwelleth righteousnes.