Enûma Eliš
In a frequently-quoted suggestion going back to the early 20th century, the Hebrew "Sabbath" is compared to the Sumerian "sa-bat" "mid-rest", a term for the full moon. The Sumerian term has been reconstructed as rendered "Sapattum" or "Sabattum" in Babylonian, possibly present in the lost fifth tablet of the Enûma Eliš, tentatively reconstructed "[Sa]bbath shalt thou then encounter, mid[month]ly".