שְׁמַ֖ע יִשְׂרָאֵ֑ל יְהוָ֥ה אֱלֹהֵ֖ינוּ יְהוָ֥ה ׀ אֶחָֽד׃
<span class="x" onmousemove="Show('perush','El Rambam explica este versículo en el <b>1º Capítulo</b> de Las Leyes del Estudio de la Torá.',event);" onmouseout="Close();"> Oye</span>, Israel: <span class="x" onmousemove="Show('perush','Este es el <b>2do Precepto Positivo</b> enumerado por el Rambam en el Prefacio a Mishné Torá, su “Compendio de la Ley Hebrea” para todo el Pueblo de Israel.',event);" onmouseout="Close();">El Señor nuestro Dios, El Señor es Uno</span>:
Mishneh Torah, Tefillin, Mezuzah and the Torah Scroll
The four Pentateuchal sections, beginning respectively, "Sanctify unto me" (Ex. 13:1-10), "And it shall be when the Lord shall bring thee" (Exodus 13:11-16)—these two being in the Book of Exodus, "Hear, O Israel" (Deuteronomy 6:4-9) "And it shall come to pass if ye shall hearken diligently" (Deuteronomy 11:13-21), are written and covered with a skin. These are called Tephillin, and are placed upon the head and bound on the arm. The omission of the point of a single letter in any one of these sections bars, according to Scriptural enactment, the use of all of them. They must all be written perfectly and in accordance with rule.
Mishneh Torah, Reading the Shema
What does one read? Three sections as follows: the section beginning, "Hear, O Israel" (Deuteronomy 6:4-9); that commencing, "And it shall come to pass" (Deuteronomy 11:13-21); and that commencing, "And the Lord spoke" (Numbers 15:37-41). The section beginning, "Hear, O Israel" is recited first, because it sets forth the duties of acknowledging the Unity of God, loving Him, and studying His words. This is the great and essential matter on which all depends. Then, the passage beginning, "And it shall come to pass" is read, this containing a charge to fulfill all the other commandments. Finally the section concerning Fringes is read, as it also contains a charge to remember all the commandments.
Mishneh Torah, Tefillin, Mezuzah and the Torah Scroll
This is the case also with the two sections of the Mezuzah, beginning respectively, "Hear, O Israel" (Deuteronomy 6:4-9) and "And it shall come to pass if ye shall hearken diligently (Deuteronomy 11:13-21). If the point of a letter is missing in these two sections, the Mezuzah may not, according to Scriptural enactment, be used. The two sections must be written perfectly. So too, a scroll of the Law, in which a single letter is missing, is unfit for use.