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.