The New Testament writers including Jesus understood that the “Day of the Lord” and the “Coming” (Parousia) denoted the same events at Christ’s Return (deliverance of the godly and judgment on the ungodly.) The two terms often emphasize different aspects of Christ’s Return — “Coming” with deliverance, and “Day of the Lord” with the judgment aspect.
Peter provides us with an excellent example in which he freely interchanges these two terms denoting the same event of the conflagration of creation:
(10) But the day of the Lord will come like a thief, in which the heavens will pass away with a roar and the elements will be destroyed with intense heat, and the earth and its works will be burned up. (11) Since all these things are to be destroyed in this way, what sort of people ought you to be in holy conduct and godliness, (12) looking for and hastening the coming (parousia) of the day of God, because of which the heavens will be destroyed by burning, and the elements will melt with intense heat. – 2Pet 3:10-12
