The earliest scriptural writings we have I believe are in the Book of Enoch but it is preserved through the ages and retranslated over and over. Another writer of scripture-like writings around the time of Enoch was Cainan (the Book of Jasher records). The earliest ‘scriptures’ found actually surviving intact from when they were written come from the descendants of Enoch. The Instructions of Sharappak is the best example we have preserved as extant text and it starts: "In those days, in those far remote days, in those nights, in those faraway nights, in those years, in those far remote years, at that time the wise one who knew how to speak in elaborate words lived in the Land; Sharappak [biblical name Lamech], the wise one, who knew how to speak with elaborate words lived in the Land. Sharappak gave instructions to his son; Sharappak, the son of Ubara-Tutu [Methuselah] gave instructions to his son Zi-ud-sura [Noah]: My son, let me give you instructions: you should pay attention! Zi-ud-sura, let me speak a word to you: you should pay attention! ..." -- translation of the 'Instructions of Sharappak', 3rd Mill BC. http://etcsl.orinst.ox.ac.uk/section5/tr561.htm . * Note: Methuselah [Ubara-Tutu] was son of Enoch [En-men-dur-anki] who was son of Jared who was son of Mahalalel who was son of Kainan (a teacher of righteousness) who was son of Enos who was son of Seth who was son of Adam [Sumerian name Alulim] who was first king of Sumer and ruled from Eridu the first city, who had no earthly parents because he was created by God. We find these people listed in the Sumerian King List, another extant document from later after the Flood ( http://etcsl.orinst.ox.ac.uk/section2/tr211.htm ), and in Genesis and in the Book of Jasher too. The latter tells that Methuselah succeeded Enoch as king of Sumer and was last king before the Flood came in Noah's time. Noah was Methuselah's grandson and Noah's father Lamech did not become king: both Jasher and Sumerian King List agree on this. Jasher tells us that Lamech (Shurappak) did not follow God as closely as Enoch and Methuselah and Noah. Yet his 'Instructions of Sharappak' writings of proverbs for his son Noah are reminiscent of scriptural proverbs in Bible scripture.
