From the Jamieson-Fausset-Brown Bible Commentary (KJV)
2 Peter 3:12. Hasting unto — with the utmost eagerness, desiring [Wahl], praying for, and contemplating, the coming Savior as at hand. The Greek may mean “hastening (that is, urging onward [Alford]) the day of God”; not that God’s eternal appointment of the time is changeable, but God appoints us as instruments of accomplishing those events which must be first before the day of God can come. By praying for His coming, furthering the preaching of the Gospel for a witness to all nations, and bringing in those whom “the long-suffering of God” waits to save, we hasten the coming of the day of God . . . . Christ says, “Surely I come quickly. Amen.” Our part is to speed forward this consummation by praying, “Even so, come, Lord Jesus” (Rev. 22:20). http://jfb.biblecommenter.com/2_peter/3.htm
