You have read the Bible, since you are quoting from it. That's a weird question to ask.
On the Lord's Day: see Isaiah 2:6-22; Ezekiel 30; Joel 2:1-11; Amos 8:9-14; Zephaniah 1:2-18,2:1-3… This is the day of final judgement, where all nations will be gathered and will be given a final punishment.
On this day being the day of the new creation, where the world will end and change to a new mode of existence: see Isaiah 24:16-23,34:1-4,51,52:1-12,65; Ezekiel 40-48; Joel 3-4; Micah 5; Haggai 2; Zachariah 12-14; Malachi 3; Psalm 102; Matthew 24:26-35; Mark 13:24-27; Luke 21:25-27; 1 Corinthians 7:25-40; 2 Peter 3:1-13; Revelation 20:7-15,21:1-8…
In the Bible, the number 7 symbolizes perfection. This page shows some examples where this number is used symbolically to give significance to something: patheos.com/blogs/christiancrier/2014/09/26/what-does-the-number-seven-7-mean-or-represent-in-the-bible/
The number 8, however, represents "beyond perfection", in other words, God. Children are circumcised 8 days after birth to represent being grafted onto the people of God, for instance. In Gematria (a numerological system to convert words to numbers, known to the Biblical authors as it is used in the book of Revelation to turn "Nero Caesar" into "666"), "Jesus" is "888".
Early Christians called the day of worship the "Day of the Lord" (Revelation 1:10) and recognized that there is an ultimate day after the 7th. (Hebrews 3:7-19,4:1-13) Their day of worship, where they had communion, was the first day of the week, that is, the day after the Sabbath. (Acts 2:46,20:7) More importantly, the Gospels are careful to portray Jesus's final time in Jerusalem as being a week long, with Him being dead during the Sabbath and resurrecting on the next day.
Finally, I want to point out that Jesus was resurrected with a glorified, spiritual body. The resurrection -has- begun, Jesus is the first-born among the resurrected, we will simply follow all at once at His second coming. (Romans 8:29; Colossians 1:18; Revelation 1:4) But when Jesus was resurrected, the world was judged - whether we resurrect with Him to partake of divine life, or we resurrect for eternal punishment, is up to whether we graft ourselves onto His death and resurrection here and now, through Baptism. (Romans 6:5-11) Therefore, even if the fullness of the Lord's Day is going to come at the end of the world, the Lord's Day has already come upon us in the resurrection of Jesus, and, when we partake of Christ's Body and Blood on Sunday, we receive our salvation or our condemnation. (1 Corinthians 10:14-17,11:17-34)