Musar su Genesi 48:5

Something similar is true of Joseph. Although Joseph himself is a branch of Jacob, he did father two of the regular tribes, i.e. Ephrayim and Menasseh, whom Jacob compared in status to Reuben and Shimon (Genesis 48, 5). When we look once more at the word אחד, we will find that Joseph was unique in having a close connection with both the letter ח i.e. the brothers of Jacob's major wives, seeing he himself was one of those. He was also closely attached to the sons of Jacob's concubines, since the Torah describes Joseph as being raised primarily among the sons of Zilpah and Bilhah (37, 2). Considering the expression והוא נער, also stressed in that verse, we find in it an allusion to something I have previously mentioned, namely that יעקב contains an allusion to the letter ו in the four-lettered Ineffable Name. The name יוסף must then be viewed as a miniature edition of that same letter in G–d's name. The scriptural allusion to this concept is found in Isaiah 10, 19 ונער יכתבם, "and a lad will write them down." [This is probably an error, and should have been a quote from Isaiah 11, 6 ונער קטן נוהג בם. Ed.]