The last day of all days after which there will be no more time is called the day of the Lord. This day is the day of ruin (1 Thes 5:3). "On that day the heavens will vanish with a roar; the elements will be destroyed by fire" (2 Pt 3:10). The day of the Lord is also the day of Christ's return. "The Lord Himself will come down from heaven at the word of command, at the sound of the archangel's voice and God's trumpet; and those who have died in Christ will rise first. Then we, the living, the survivors, will be caught up with them in the clouds to meet the Lord in the air" (1 Thes 4:16-17). Therefore, the day of the Lord is also the day of resurrection for those who have died in Christ and of the assumption into the air for those Christians still living. Finally, the day of the Lord will be the day of judgment (see Mt 25:31ff) and the day of eternal salvation (Heb 9:28) or everlasting damnation (see Mt 25:46).
Although the day of the Lord is the day of ruin, return, resurrection, assumption, judgment, salvation, and damnation, it is primarily the day of the Lord. The Lord Jesus should be the Focus of the last day, today, and all our days. If we have totally given our lives to the Lord, we won't have to fear the last day. We can cry out: "Maranatha!" "Come, Lord Jesus!" (Rv 22:20)