Halakhah su Deuteronomio 6:6

According to most Rishonim, the biblical commandment can be fulfilled by reciting just the “Shema Yisrael” verse, for about that verse Torah says (Devarim 6:6-7), “These words I am commanding you today must be in your heart…when you lie down and when you get up.” However, the Sages ordained the recitation of all three paragraphs. It can therefore be explained that the essence of the mitzva of Shema is indeed the acceptance of the yoke of heaven, which is why most Rishonim maintain that even one who only recites the first verse fulfills the biblical commandment. Yet, the more one enhances his acceptance of the yoke of heaven, the more completely he fulfills the biblical mitzva. Therefore, the Sages ordained the recitation of all three paragraphs, for within them are the fundamentals of faith, the acceptance of the yoke of the mitzvot, and the remembrance of all the mitzvot through the mitzva of tzitzit. Hence, in truth, we fulfill the biblical mitzva by reciting all three paragraphs (Peninei Halakha: Prayer, ch. 15 n. 1).

That is that He commanded us about loving Him, may He be exalted. And that is that we think about and contemplate His commandments, His statements and His actions until we comprehend Him and derive the greatest pleasure from that comprehension. And that is the love that is obligated. And the language of the Sifrei (Sifrei Devarim 33:1) is, "Since it is stated, 'And you shall love,' I would not know how a man is to love the Omnipresent. [Hence] we learn to say, 'And these things that I command you today shall be upon your heart' (Deuteronomy 6:6) - that through this, you will recognize the One that spoke and the world [came into being]." Behold we have explained to you that comprehension will come to you through contemplation and you will [then] come to pleasure, and perforce the love will come. And we have already clarified that this commandment also includes that we call all people to His service, may He be exalted, and to believe in Him. And that is since when you love a person, you will recount his praises and magnify him, and call on other people to love him. And this is, by way of analogy, the same with true love of Him, may He be exalted: When comprehension of His truth comes to you, you without a doubt call out to the fools and silly ones to know the true knowledge that you know. And the language of the Sifrei (Sifrei Devarim 32:2) is, "'And you shall love the Lord, your God' - cause Him to be loved by the creatures, like your father Avraham (did); as it is stated (Genesis 12:5), 'and the souls that they had made in Charan.'" And it means to say: Like Avraham who loved [God] - as Scripture testifies, "Avraham, who loves me" (Isaiah 41:8), and this was from his great comprehension - to the point that he called people to Him. (See Parashat Vaetchanan; Mishneh Torah, Foundations of the Torah 2.)

One’s primary kavana must be for the first verse, because in saying it we accept the yoke of heaven, as the Torah says: “These words… must be in your heart” (Devarim 6:6). Therefore, one must concentrate in her heart on the words she recites in the first verse. If she did not focus on the words she recited, she did not perform the mitzva (Berakhot 13b; SA 60:5, 63:4).