The Talmud (Sanhedrin 74a) states:
Rabbi Eliezer asked (in reference to the verse (Devorim 6:5), “You shall love Hashem your G-d with all your soul and all your resources”): If it is stated “with all your soul (nafshecha),” why was it necessary to state “with all your resources (me’odecha)”? And if it is stated “with all your resources,” why was it necessary to state “with all your soul”? Rather, [the explanation is that] if there is a person whose life is more precious to him than his money, it says “with all your soul” [so that he be prepared to give up that which is most precious to him]. And if there is a person whose money is more precious to him than his life, it says “with all your resources” [so that he be prepared to give up that which is most precious to him].
This means that your love for Him should be more precious to you than everything else that is precious to you.
It would seem that this is not only a lesson about the importance of giving one’s life or resources for Hashem—what one should be willing to give up. Here, the Talmud teaches us how important it is to love Hashem, and how central this focus should be in our lives. It should both act as a guideline for every single aspect of life, and as a goal to which a Jew should aspire: that his love of Hashem should reach the highest level possible.
Yes, as mere mortals we have natural desires, preferences, and inclinations. And these are not only desires for indulgence (along the lines of the one who values his money above all else), but for constructive things as well (along the lines of the one who values his life above all else). Nevertheless, since all these things are about what I want, they should be relegated to second-class status. One’s love of Hashem should be the overriding concern in any and every aspect of life.
And here the emphasis is not fear, but love. Fear of Hashem should precede love of Hashem, of course, as it is the foundation of one’s divine service (see the beginning of chapter 41 of Tanya). This means first and foremost strict adherence to the requirements of halacha. However, following halacha is merely step one. Fear is primarily about not violating the minimum, or, in other words, not sinning and rebelling.
In contrast, love implies going beyond the letter of the law and the call of duty. One who truly feels love does not constantly calculate whether he is technically obligated to assist his loved one—that would show that love is lacking. Rather, he naturally, of his own initiative, volunteers to help out his loved one. He does not regard it as discharging an obligation, but as a privilege and a pleasure.
Likewise, loving Hashem means naturally asking oneself: “What can I do to give Hashem pleasure? What will make Him rejoice and be proud that I am His child?” One who doesn’t feel the desire to ask oneself this should at least aim and strive to reach this level. In the meantime it would seem that one ought to at least ask himself this question in a somewhat more forced manner, for it accustoms oneself to this way of thinking.
This is the main thought that should guide and dominate a Jew’s actions and choices—even if it means forgoing something he would otherwise very much prefer to have.