3:12 hasting unto the coming. That is, “hastening the coming.” From the human perspective, we can hasten the return of Christ by helping to win converts to Him. The reason why He has not already fulfilled “the promise of His coming” (II Peter 3:4) is because He is waiting for all the elect to “come to repentance” (II Peter 3:9).
3:12 heavens being on fire. The “heavens” here probably refer only to the atmospheric heavens, whose elements (hydrogen, oxygen, nitrogen, etc.) must also be “dissolved” (literally “unloosed”), since they are also presently under “the bondage of corruption” (Romans 8:20-22) and must be cleansed and renewed just as the elements of the earth. It is even possible that the purging will dissolve and cleanse the starry heavens also, since these once were the domain of “the angels that sinned” (II Peter 2:4) and since “the whole creation” (Romans 8:22) is now in bondage to the law of decay.
3:12 elements. The word “elements” is translated from the Greek stoicheion, meaning “fundamental constituents” and implies an orderly arrangement of these basic entities. Ever since the primeval curse, which affected even “the dust of the ground” (Genesis 2:7; 3:17), out of which all things had been made, this orderly arrangement has been deteriorating slowly. The disintegration process will be speeded up and completed in the great “dissolving.” This will not be annihilation, however, for God does not “uncreate” what He created. “Whatsoever God doeth, it shall be forever” (Ecclesiastes 3:14). His basic principle of conservation of mass/energy, the most basic and pervasive law known to science, will still hold; Christ will still be “upholding all things by the word of His power” (Hebrews 1:3).