The reference from Peter's word in 2nd Peter 3:8-9
An accepted book of teaching by many in the early church was the Epistle of Barnabas, attributed to the Barnabas in the Book of Acts.
Barnabas 15:3 "Sanctified" (from the Hebrew word qadesh) means holy, hallowed, separated. Thus in Verse 4, Barnabas expands further on the meaning of the Sabbath.
Barnabas 15:4
Of the Sabbath He speaks in the beginning of the creation; And God made the
works of His hands in six days, and He ended on the seventh day, and rested on
it, and He sanctified it.
Seen in a bad way with that derived word prostitute in
Seen in a good way in Exodus 3:5. "the place whereon you stand is holy ground"
Give heed, children, what this means; He ended in six days. He means
this, that in six thousand years the Lord shall bring all things to an end; for
the day with Him signifies a thousand years; and this He himself bears me
witness, saying; Behold, the day of the Lord shall be as a thousand years.
Therefore, children, in six days, that is in six thousand years, everything
shall come to an end.
Barnabas 15:5
And He rested on the seventh day. this He means; when His Son shall
come, and shall abolish the time of the Lawless One, and shall judge the
ungodly, and shall change the sun and the moon and the stars, then shall he
truly rest on the seventh day.
Barnabas was doubtless familiar with the Lord's words to Enoch in the Second Book of Enoch, a part of the Jewish Apocrypha at the time of the early church. http://reluctant-messenger.com/2enoch01-68.htm#Chapter33 And I appointed the eighth day also, that
the eighth day should be the first-created after my work, and that the first
seven revolve in the form of the seventh thousand, and that at the
beginning of the eighth thousand there should be a time of not-counting,
endless, with neither years nor months nor weeks nor days nor hours. So while
those last two books aren't part of scripture, they show that the Jews, and early tribes everywhere (even the early Mayans with their soon to end calendar) knew of the prophecies of the Lord's coming, and judgment, and 1,000 year reign End of Report