Book of Jubilees 49:15
And do thou command the children of Israel to observe the passover throughout their days, every year, once a year on the day of its fixed time, and it shall come for a memorial well pleasing before the Lord, and no plague shall come upon them to slay or to smite in that year in which they celebrate the passover in its season in every respect according to His command.
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.