Midrash for Sanhedrin 41:10
וקאמר ליה נביא (שמואל ב יב, ח) אם מעט ואוסיפה לך כהנה וכהנה כהנה שית וכהנה שית דהוו להו תמני סרי
It has indeed beentaught likewise: 'He shall not multiply wives to himself beyond twenty-four.'And according to him who interprets the redundant'<i>waw</i>',<span class="x" onmousemove="('comment',' In 'we-kahennah'. The prefix 'waw' between two words or sentences at the beginning of a chapter, which does not necessarily express their relations to one another, is used for interpretation by some Sages. v. infra 51b. ');"><sup>18</sup></span> it ought to be forty-eight.And it has been taught even so: 'He shall not multiply wives to himself,more than forty-eight.' Then what is the reason of the Tanna of our Mishnah?— R. Kahana said: He parallels the second 'kahennah' with the first; thus,just as the first 'kahennah' indicates [an increase of] six, so does thesecond. But there was Michaltoo!<span class="x" onmousemove="('comment',' Additional to the six wives enumerated. ');"><sup>19</sup></span>