Reference for Kiddushin 59:10
לעולם ישלש אדם שנותיו שליש במקרא שליש במשנה שליש בתלמוד מי יודע כמה חיי לא צריכא ליומי
because they used to count all the letters of the Torah.<span class="x" onmousemove="('comment',' To safeguard the correctness of the text. Soferim is taken in the original sense of its root safar, 'to count'.');"><sup>19</sup></span> Thus, they said, the waw in gahon<span class="x" onmousemove="('comment',' Whatsoever goeth upon the belly (iujd) - Lev. XI, 42.');"><sup>20</sup></span> marks half the letters of the Torah; darosh darash,<span class="x" onmousemove="('comment',' Lev. X, 16: And Moses diligently enquired after - darosh darash - the goat of the sin-offering.');"><sup>21</sup></span> half the words; we-hithggalah,<span class="x" onmousemove="('comment',' Lev. XIII, 33: we-hithggalah, then he shall be shaven. [In M.T. the words 'he placed on him' (Lev. VIII, 8) is given as the middle verse.]');"><sup>22</sup></span>