*lost*, here's a few extrabiblical uses of the Tetragrammaton. There's many more.
Extrabiblical use of the Tetragrammaton
1) The Tetragrammaton repeatedly appears on the Stele of Mesha`, king of Moab (ca. 900 BCE). This stele contains a text with the oldest Hebrew-Phoenician script ever discovered. This stele is of the utmost importance for linguists because it is the only remaining, historical monument of the Moabite kingdom. It contains an account of the historical relationship between Moab and Israel.... It reveals Moabite as a Semitic dialect, virtually identical with Hebrew, serving as proof of an advanced written language of an insignificant kingdom far removed from the historical routes of the ninth century BCE (see G.R. Driver, Semitic Writing, 1976, p. 109).
The text reads: “I, Mesha, the son of Chemosh-[....], king of Moab, the Dibonite.... Omri, the king of Israel, humiliated Moab for many days.... And I took the utensils of YHWH and dragged them before Chemosh.” (...w'qhh msm '[t k]ly yhwh w'shhb hm lpny kms). Cf. Is. 52:11. It is probably the earliest occurrence of the Tetragrammaton outside the Bible.
2) In the Semitic Museum of Harvard there is an eighth century seal with the inscription lmqnyw `bd.yhwh, “belonging to Miqnejaw, the servant of yhwh”. The name seems to be Levitical (cf. 1 Chron. 15:18, 21); the owner of the seal might have been a priest, serving in the sanctuary.
3) A funerary inscription of Khirbet el-Qôm (ca. 750 BCE), southwest of Lachish, containing the words brk 'wryhw lyhwh “blessed be Urijahu by yhwh.”
4) An inscription in four fragments, found at Kuntillat `Ajrud near the Sinai Peninsula, contains the words hhyb yhwh and the divine name “Ba`al” in Phoenician letters.
5) The Tetragrammaton is freely used in the Lachish Letters (ca. 600 BCE). They consist of 18 ostraca with formulae, containing the Tetragrammaton. The text is written in Old Hebrew characters. One of the ostraca (nr. IV) reads: “May yhwh make my lord hear good news soon (ysm` yhwh 't 'ny s[m]`t slm `t kym `t kym) ....we are on the look-out for fire signals from Lachish....” yr' yhwh 't 'dny 't h`t hzh slm “may yhwh allow my lord to enjoy good health”. The general OT formula hhy yhwh “As yhwh lives!” also appears in these, once with Biblical spelling and once with an eccentric spelling hhyhwh. This form hhyhwh (=hy yhwh) indicates that when two identical letters appear next to each other, they are often written as one (scriptio continua), even when they were part of two separate words, or in case of haplography. The name also occurs in the context ybrk yhwh ’t ’[??] y, an unexplained passage, and possibly also in a badly damaged portion of a text.
6) The Arad archives contains two references to yhwh, the first in an introductory greeting `l 'dny 'lysb yhwh ys'l lslmk (lines 1 - 3), “To my lord Eljashib; may yhwh seek your peace” (lit. “ask after”, probably equivalent to “grant”; cf. 1 Sam.1:28 and a similar formula in Aramaic), the second in lines 7 - 10: wldbr 'sr swtny slm byt yhwh h' ysb, “And as for the matter concerning which you commanded me – it has been settled. In the house of yhwh he remains.”
7) The most difficult of the pre-exilic uses of the Tetragrammaton occurs in some wall inscriptions from Khirbet Beit Lei, a few miles from Lachish. Inscription A, as given by Cross, reads: [']ny yhwh 'lhykh 'rsh `ry yhdh wg'lty yrslm, “I am yhwh, your God, I will accept the cities of Judah and I will redeem Jerusalem”. Cross reads text B as follows: nqh yh 'l hhnn nqh yh yhwh “Absolve [us] O merciful God; forgive [us] yhwh”. Text C reads as follows: hws` yhwh, “Deliver [us] yhwh”.
8) The remaining occurrences are limited to Aramaic texts of Egypt. Two spellings of the divine name occur. yhw (usually in papyri) and yhh (once in a papyrus, otherwise on ostraca). The spelling yh, attested once, is probably the result of the fading of original yhw. Both variations occur in theElephantine Papyri (ca. 500 BCE). These Aramaic documents inform us of “a Jewish military colony” on the island Elephantine on the Nile, opposite Aswan. There existed a temple where the God yhw was worshiped. Two people are mentioned in the text, khny' zy yhw 'lh', “priest of the god yhw”. The term lhhn servant of yhw possibly refers to a religious office.
Thus some 19 occurrences of the Tetragrammaton in the form of yhwh bear witness to the reliability of the MT in this respect; more may be expected, notably from the Arad archives.
9) Variations of the Tetragrammaton occur on coins (especially coins of the Maccabees).