וְאָ֣הַבְתָּ֔ אֵ֖ת יְהוָ֣ה אֱלֹהֶ֑יךָ בְּכָל־לְבָבְךָ֥ וּבְכָל־נַפְשְׁךָ֖ וּבְכָל־מְאֹדֶֽךָ׃
너는 마음을 다하고 성품을 다하고 힘을 다하여 네 하나님 여호와를 사랑하라
Or HaChaim
את בנך את יחידך, "your son, your only one, the one you love, Isaac." Here the Torah alludes to three levels of love that G'd demands of each Jew, i.e. to love G'd with all his heart, all his soul, and all his financial resources (Deut. 6,5). The word בנך alludes to the heart; nothing is closer to a man's heart than the love for his children. Concerning love with one's soul, the Torah mentions יחידך; when a person has no children he is alone and considered as dead. Love with one's soul is therefore love with the only thing one has left to love with. The words אשר אהבת refer to one's possessions; G'd meant that Abraham loved Isaac more than all his other possessions. G'd's test consisted of Abraham demonstrating that though he loved Isaac from all these perspectives he was yet willing to give him up to G'd in the form of a total offering.
Rabbeinu Yonah
"Rather be as servants who are serving the master in order not to receive a reward": (Editor's note: In my opinion, here there should be the words, "And it is difficult according to this textual variant.") Since a person should not do the commandment with the understanding that he will not receive a reward for them. But rather the [correct] textual variant is "not in order to receive a reward" - that he should not do the commandments for the sake of the reward, even though he should think that there will be recompense for his service. However, it appears to me that the variant of the books is the main one [that we should follow]: As we find such service among people, such that a purchased slave is obligated to do service without receiving reward. So too, a man must serve God in order not to receive a reward, but rather because of the kindness that He has already performed for him. And also due to the greatness of the Master, that He is fitting for this, and this is the service of God - may He be blessed and elevated - from love, as it is stated (Deuteronomy 6:5), "And you shall love the Lord." And what is complete service among people? One who wants to serve his friend because of his love for him from earlier days, and even if he knows that he will not give him a reward. And [with] this type of love should a person love the service of God. And therefore, [the Mishnah] placed it adjacent to the matter of fear and stated,
Bartenura
יחזור למקום שטעה – If between each section [of the Shema] he erred and did not know on which section he had interrupted (the appropriate order), and to which paragraph’s beginning he should return to, he should go back to the first interval – which is “והיה אם שמוע” (Deuteronomy 11:13-21). And Maimonides states that this is the first sentence: “ואהבת את ה' אלהיך” (Deuteronomy 6:5), and if he is in the middle of a section, he should stop [assuming that] he knows which section (of the Shema) that he is in, but if he doesn’t know which place and from which section he is in, he should stop and return to the beginning of that section. If he was reciting: “וכתבתם [על מזוזות]” and did not know if it was referring did not know if it was referring to “and you shall inscribe them” from the first section of the Shema (Deuteronomy 6:9) or the second section of the Shema (Deuteronomy 11:20), he should go back to the first mention of “you shall inscribe them” (Deuteronomy 6:9). But if he became doubtful after he had begun (the concluding verse of the second section of the Shema), “to the end that you and your children may endure” (Deuteronomy 11:21), he should not go back, since he is following the natural flow of the language [of the Shema].