Reference for Sanhedrin 140:4
ומה בר נדרי כל נשים של בית אביך היו נודרות יהא לי בן הגון למלכות ואני נדרתי ואמרתי יהא לי בן זריז וממולא בתורה והגון לנביאות
'And what, the son of my womb?' All the women of thy father's harem, as soon as they conceived, no longer saw the king, but I forced myself in, so that my child might be vigorous and fair-skinned.<span class="x" onmousemove="('comment',' And now he was employing his very strength and beauty in evil courses. ');"><sup>7</sup></span> 'And what, the son of my vows?' All the women of thy father's household made vows [praying] that they might bear a son fit for the throne, but I vowed praying that I might bear a son zealous and filled with the knowledge of the Torah and fit for prophecy. It is not for Kings, O Lemuel, it is not for kings to drink wine, nor for princes [to say,] Where is strong drink?<span class="x" onmousemove="('comment',' Ibid. 3. ');"><sup>8</sup></span>