ואהבת The First Paragraph of the Shema

(1) A person should not say: "I will fulfill the mitzvot of the Torah and occupy myself in its wisdom in order to receive all the blessings which are contained within it or in order to merit the life of the world to come."
"[Similarly,] I will separate myself from all the sins which the Torah warned against so that I will be saved from all the curses contained in the Torah or so that [my soul] will not be cut off from the life of the world to come."
It is not fitting to serve God in this manner. A person whose service is motivated by these factors is considered one who serves out of fear. He is not on the level of the prophets or of the wise.
The only ones who serve God in this manner are common people, women, and minors. They are trained to serve God out of fear until their knowledge increases and they serve out of love.

(2) One who serves [God] out of love occupies himself in the Torah and the mitzvot and walks in the paths of wisdom for no ulterior motive: not because of fear that evil will occur, nor in order to acquire benefit. Rather, he does what is true because it is true, and ultimately, good will come because of it.
This is a very high level which is not merited by every wise man. It is the level of our Patriarch, Abraham, whom God described as, "he who loved Me," for his service was only motivated by love.
God commanded us [to seek] this rung [of service] as conveyed by Moses as [Deuteronomy 6:5] states: "Love God, your Lord.'' When a man will love God in the proper manner, he will immediately perform all of the mitzvot motivated by love.

(3) What is the proper [degree] of love? That a person should love God with a very great and exceeding love until his soul is bound up in the love of God. Thus, he will always be obsessed with this love as if he is lovesick.
[A lovesick person's] thoughts are never diverted from the love of that woman. He is always obsessed with her; when he sits down, when he gets up, when he eats and drinks. With an even greater [love], the love for God should be [implanted] in the hearts of those who love Him and are obsessed with Him at all times as we are commanded [Deuteronomy 6:5: "Love God...] with all your heart and with all soul."
This concept was implied by Solomon [Song of Songs 2:5] when he stated, as a metaphor: "I am lovesick." [Indeed,] the totality of the Song of Songs is a parable describing [this love].

We learned in our mishna the explanation of the verse: “And you shall love the Lord your God with all your heart and all your soul and all your might” (Deuteronomy 6:5). This was elaborated upon when it was taught in a baraita: Rabbi Eliezer says: If it is stated: “With all your soul,” why does it state: “With all your might”? Conversely, if it stated: “With all your might,” why does it state: “With all your soul”? Rather, this means that if one’s body is dearer to him than his property, therefore it is stated: “With all your soul”; one must give his soul in sanctification of God. And if one’s money is dearer to him than his body, therefore it is stated: “With all your might”; with all your assets.

Rabbi Akiva says: “With all your soul” means: Even if God takes your soul.

The Gemara relates at length how Rabbi Akiva fulfilled these directives. The Sages taught: One time, after the bar Kokheva rebellion, the evil empire of Rome decreed that Israel may not engage in the study and practice of Torah. Pappos ben Yehuda came and found Rabbi Akiva, who was convening assemblies in public and engaging in Torah study. Pappos said to him: Akiva, are you not afraid of the empire? Rabbi Akiva answered him: I will relate a parable. To what can this be compared? It is like a fox walking along a riverbank when he sees fish gathering and fleeing from place to place.
The fox said to them: From what are you fleeing?
They said to him: We are fleeing from the nets that people cast upon us.
He said to them: Do you wish to come up onto dry land, and we will reside together just as my ancestors resided with your ancestors?
The fish said to him: You are the one of whom they say, he is the cleverest of animals? You are not clever; you are a fool. If we are afraid in the water, our natural habitat which gives us life, then in a habitat that causes our death, all the more so.
The moral is: So too, we Jews, now that we sit and engage in Torah study, about which it is written: “For that is your life, and the length of your days” (Deuteronomy 30:20), we fear the empire to this extent; if we proceed to sit idle from its study, as its abandonment is the habitat that causes our death, all the more so will we fear the empire. The Sages said: Not a few days passed until they seized Rabbi Akiva and incarcerated him in prison, and seized Pappos ben Yehuda and incarcerated him alongside him. Rabbi Akiva said to him: Pappos, who brought you here? Pappos replied: Happy are you, Rabbi Akiva, for you were arrested on the charge of engaging in Torah study. Woe unto Pappos who was seized on the charge of engaging in idle matters. The Gemara relates: When they took Rabbi Akiva out to be executed, it was time for the recitation of Shema. And they were raking his flesh with iron combs, and he was reciting Shema, thereby accepting upon himself the yoke of Heaven. His students said to him: Our teacher, even now, as you suffer, you recite Shema? He said to them: All my days I have been troubled by the verse: With all your soul, meaning: Even if God takes your soul. I said to myself: When will the opportunity be afforded me to fulfill this verse? Now that it has been afforded me, shall I not fulfill it? He prolonged his uttering of the word: One, until his soul left his body as he uttered his final word: One. A voice descended from heaven and said: Happy are you, Rabbi Akiva, that your soul left your body as you uttered: One. The ministering angels said before the Holy One, Blessed be He: This is Torah and this its reward? As it is stated: “From death, by Your hand, O Lord, from death of the world” (Psalms 17:14); Your hand, God, kills and does not save. God said the end of the verse to the ministering angels: “Whose portion is in this life.” And then a Divine Voice emerged and said: Happy are you, Rabbi Akiva, as you are destined for life in the World-to-Come, as your portion is already in eternal life.