Book of Jubilees 2:19
And He said unto us: 'Behold, I will separate unto Myself a people from among all the peoples, and these shall keep the Sabbath day, and I will sanctify them unto Myself as My people, and will bless them; as I have sanctified the Sabbath day and do sanctify (it) unto Myself, even so will I bless them, and they shall be My people and I will be their God.
Background and history of Book of Jubilees, and issues with this book.
R. H. Charles, The Book of Jubilees, in The Apocrypha and Pseudepigrapha of the Old Testament, vol. 2 (Oxford: Clarendon Press, 1913). Public domain in the United States (published 1913). Charles died in 1931, so the book is in the public domain in the United Kingdom. The verse text is the Joshua Williams transcription at pseudepigrapha.com. Jubilees 1:8 and 1:9 are divided at the break in the 1902 Clarendon scan (archive.org bookofjubileesor00char), where verse 9 begins “For they will forget.” That scan also numbers the angel-of-the-presence sentence as 1:29. Editorial brackets in the translation are Charles’s.