Halacha

הלכה א
אַל יֹאמַר אָדָם הֲרֵינִי עוֹשֶׂה מִצְוֹת הַתּוֹרָה וְעוֹסֵק בְּחָכְמָתָהּ כְּדֵי שֶׁאֲקַבֵּל כָּל הַבְּרָכוֹת הַכְּתוּבוֹת בָּהּ אוֹ כְּדֵי שֶׁאֶזְכֶּה לְחַיֵּי הָעוֹלָם הַבָּא, וְאֶפְרשׁ מִן הָעֲבֵרוֹת שֶׁהִזְהִירָה תּוֹרָה מֵהֶן כְּדֵי שֶׁאֶנָּצֵל מִן הַקְּלָלוֹת הַכְּתוּבוֹת בַּתּוֹרָה אוֹ כְּדֵי שֶׁלֹּא אֶכָּרֵת מֵחַיֵּי הָעוֹלָם הַבָּא. אֵין רָאוּי לַעֲבֹד אֶת ה' עַל הַדֶּרֶךְ הַזֶּה, שֶׁהָעוֹבֵד עַל דֶּרֶךְ זֶה הוּא עוֹבֵד מִיִּרְאָה וְאֵינָהּ מַעֲלַת הַנְּבִיאִים וְלֹא מַעֲלַת הַחֲכָמִים. וְאֵין עוֹבְדִים ה' עַל דֶּרֶךְ זֶה אֶלָּא עַמֵּי הָאָרֶץ וְהַנָּשִׁים וְהַקְּטַנִּים שֶׁמְּחַנְּכִין אוֹתָן לַעֲבֹד מִיִּרְאָה עַד שֶׁתִּרְבֶּה דַּעְתָּן וְיַעַבְדוּ מֵאַהֲבָה:
כסף משנה
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.

הלכה ב
הָעוֹבֵד מֵאַהֲבָה עוֹסֵק בַּתּוֹרָה וּבַמִּצְוֹת וְהוֹלֵךְ בִּנְתִיבוֹת הַחָכְמָה לֹא מִפְּנֵי דָּבָר בָּעוֹלָם וְלֹא מִפְּנֵי יִרְאַת הָרָעָה וְלֹא כְּדֵי לִירַשׁ הַטּוֹבָה אֶלָּא עוֹשֶׂה הָאֱמֶת מִפְּנֵי שֶׁהוּא אֱמֶת וְסוֹף הַטּוֹבָה לָבוֹא בִּגְלָלָהּ. וּמַעֲלָה זוֹ הִיא מַעֲלָה גְּדוֹלָה מְאֹד וְאֵין כָּל חָכָם זוֹכֶה לָהּ. וְהִיא מַעֲלַת אַבְרָהָם אָבִינוּ שֶׁקְּרָאוֹ הַקָּדוֹשׁ בָּרוּךְ הוּא אוֹהֲבוֹ לְפִי שֶׁלֹּא עָבַד אֶלָּא מֵאַהֲבָה. וְהִיא הַמַּעֲלָה שֶׁצִּוָּנוּ בָּהּ הַקָּדוֹשׁ בָּרוּךְ הוּא עַל יְדֵי משֶׁה שֶׁנֶּאֱמַר (דברים ו ה) "וְאָהַבְתָּ אֵת ה' אֱלֹהֶיךָ". וּבִזְמַן שֶׁיֶּאֱהֹב אָדָם אֶת ה' אַהֲבָה הָרְאוּיָה מִיָּד יַעֲשֶׂה כָּל הַמִּצְוֹת מֵאַהֲבָה:
כסף משנה
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.

הלכה ג
וְכֵיצַד הִיא הָאַהֲבָה הָרְאוּיָה. הוּא שֶׁיֹּאהַב אֶת ה' אַהֲבָה גְּדוֹלָה יְתֵרָה עַזָּה מְאֹד עַד שֶׁתְּהֵא נַפְשׁוֹ קְשׁוּרָה בְּאַהֲבַת ה' וְנִמְצָא שׁוֹגֶה בָּהּ תָּמִיד כְּאִלּוּ חוֹלֶה חֳלִי הָאַהֲבָה שֶׁאֵין דַּעְתּוֹ פְּנוּיָה מֵאַהֲבַת אוֹתָהּ אִשָּׁה וְהוּא שׁוֹגֶה בָּהּ תָּמִיד בֵּין בְּשִׁבְתּוֹ בֵּין בְּקוּמוֹ בֵּין בְּשָׁעָה שֶׁהוּא אוֹכֵל וְשׁוֹתֶה. יֶתֶר מִזֶּה תִּהְיֶה אַהֲבַת ה' בְּלֵב אוֹהֲבָיו שׁוֹגִים בָּהּ תָּמִיד כְּמוֹ שֶׁצִּוָּנוּ בְּכָל לְבָבְךָ וּבְכָל נַפְשְׁךָ. וְהוּא שֶׁשְּׁלֹמֹה אָמַר דֶּרֶךְ מָשָׁל (שיר השירים ב ה) "כִּי חוֹלַת אַהֲבָה אָנִי". וְכָל שִׁיר הַשִּׁירִים מָשָׁל הוּא לְעִנְיָן זֶה:
כסף משנה
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].

הלכה ד
אָמְרוּ חֲכָמִים הָרִאשׁוֹנִים שֶׁמָּא תֹּאמַר הֲרֵינִי לָמֵד תּוֹרָה בִּשְׁבִיל שֶׁאֶהְיֶה עָשִׁיר בִּשְׁבִיל שֶׁאֶקְרָא רַבִּי בִּשְׁבִיל שֶׁאֲקַבֵּל שָׂכָר בָּעוֹלָם הַבָּא. תַּלְמוּד לוֹמַר (דברים יא יג) "לְאַהֲבָה אֶת ה'". כָּל מַה שֶּׁאַתֶּם עוֹשִׂים לֹא תַּעֲשׂוּ אֶלָּא מֵאַהֲבָה. וְעוֹד אָמְרוּ חֲכָמִים בְּמִצְוֹתָיו חָפֵץ מְאֹד וְלֹא בִּשְׂכַר מִצְוֹתָיו. וְכֵן הָיוּ גְּדוֹלֵי הַחֲכָמִים מְצַוִּים לִנְבוֹנֵי תַּלְמִידֵיהֶם וּמַשְׂכִּילֵיהֶם בְּיִחוּד אַל תִּהְיוּ כַּעֲבָדִים הַמְשַׁמְּשִׁים אֶת הָרַב וְכוּ' אֶלָּא מִפְּנֵי שֶׁהוּא הָרַב רָאוּי לְשַׁמְּשׁוֹ כְּלוֹמַר עִבְדוּ מֵאַהֲבָה:
כסף משנה
4.
The Sages of the previous generations declared: Should one say: "I will study Torah in order that I become wealthy, in order that I be called a Rabbi, or in' order that I receive reward in the world to come?" The Torah teaches [Deuteronomy 11:13]: "[If you are careful to observe My commandments...] to love God; [implying] that all that you do should only be done out of love.
The Sages also said: [Psalms 112:1 instructs:] "Desire His commandments greatly." [Desire His commandments] and not the reward [which comes from] His commandments.
In a similar manner, the great Sages would command the more understanding and brilliant among their students in private: "‘Do not be like servants who serve their master [for the sake of receiving a reward].’ Rather, since He is the Master, it is fitting to serve Him;" i.e., serve [Him] out of love.

הלכה ה
כָּל הָעוֹסֵק בַּתּוֹרָה כְּדֵי לְקַבֵּל שָׂכָר אוֹ כְּדֵי שֶׁלֹּא תַּגִּיעַ עָלָיו פֻּרְעָנוּת הֲרֵי זֶה עוֹסֵק שֶׁלֹּא לִשְׁמָהּ. וְכָל הָעוֹסֵק בָּהּ לֹא לְיִרְאָה וְלֹא לְקַבֵּל שָׂכָר אֶלָּא מִפְּנֵי אַהֲבַת אֲדוֹן כָּל הָאָרֶץ שֶׁצִּוָּה בָּהּ הֲרֵי זֶה עוֹסֵק בָּהּ לִשְׁמָהּ. וְאָמְרוּ חֲכָמִים לְעוֹלָם יַעֲסֹק אָדָם בַּתּוֹרָה וַאֲפִלּוּ שֶׁלֹּא לִשְׁמָהּ שֶׁמִּתּוֹךְ שֶׁלֹּא לִשְׁמָהּ בָּא לִשְׁמָהּ. לְפִיכָךְ כְּשֶׁמְּלַמְּדִין אֶת הַקְּטַנִּים וְאֶת הַנָּשִׁים וּכְלַל עַמֵּי הָאָרֶץ אֵין מְלַמְּדִין אוֹתָן אֶלָּא לַעֲבֹד מִיִּרְאָה וּכְדֵי לְקַבֵּל שָׂכָר, עַד שֶׁתִּרְבֶּה דַּעְתָּן וְיִתְחַכְּמוּ חָכְמָה יְתֵרָה מְגַלִּים לָהֶם רָז זֶה מְעַט מְעַט וּמַרְגִּילִין אוֹתָן לְעִנְיָן זֶה בְּנַחַת עַד שֶׁיַּשִּׂיגוּהוּ וְיֵדְעוּהוּ וְיַעַבְדוּהוּ מֵאַהֲבָה:
כסף משנה
5.
Anyone who occupies himself with the Torah in order to receive reward or in order to protect himself from retribution is considered as one who is not occupied for the God's sake.
[In contrast,] anyone who occupies himself with it, not because of fear, nor to receive a reward, but rather because of his love for the Lord of the entire earth who commanded it, is one who occupies himself for God's sake.
Nevertheless, our Sages declared: A person should always occupy himself with the Torah even when it is not for God's sake for out of [service which is not intended] for God's sake will come service that is intended for God's sake.
Therefore, when one teaches children, women, and most of the common people, one should teach them to serve out of fear and in order to receive a reward. As their knowledge grows and their wisdom increases, this secret should be revealed to them [slowly,] bit by bit. They should become accustomed to this concept gradually until they grasp it and know it and begin serving [God] out of love.

הלכה ו
דָּבָר יָדוּעַ וּבָרוּר שֶׁאֵין אַהֲבַת הַקָּדוֹשׁ בָּרוּךְ הוּא נִקְשֶׁרֶת בְּלִבּוֹ שֶׁל אָדָם עַד שֶׁיִּשְׁגֶּה בָּהּ תָּמִיד כָּרָאוּי וְיַעֲזֹב כָּל מַה שֶּׁבָּעוֹלָם חוּץ מִמֶּנָּה. כְּמוֹ שֶׁצִּוָּה וְאָמַר בְּכָל לְבָבְךָ וּבְכָל נַפְשְׁךָ. אֵינוֹ אוֹהֵב הַקָּדוֹשׁ בָּרוּךְ הוּא אֶלָּא בְּדַעַת שֶׁיְּדָעֵהוּ. וְעַל פִּי הַדֵּעָה תִּהְיֶה הָאַהֲבָה אִם מְעַט מְעַט וְאִם הַרְבֵּה הַרְבֵּה. לְפִיכָךְ צָרִיךְ הָאָדָם לְיַחֵד עַצְמוֹ לְהָבִין וּלְהַשְׂכִּיל בְּחָכְמוֹת וּתְבוּנוֹת הַמּוֹדִיעִים לוֹ אֶת קוֹנוֹ כְּפִי כֹּחַ שֶׁיֵּשׁ בָּאָדָם לְהָבִין וּלְהַשִּׂיג כְּמוֹ שֶׁבֵּאַרְנוּ בְּהִלְכוֹת יְסוֹדֵי הַתּוֹרָה:
כסף משנה
6.
It is a well-known and clear matter that the love of God will not become attached within a person's heart until he becomes obsessed with it at all times as is fitting, leaving all things in the world except for this. This was implied by the command [Deuteronomy 6:5: "Love God, your Lord,] with all your heart and all your soul.
One can only love God [as an outgrowth] of the knowledge with which he knows Him. The nature of one's love depends on the nature of one's knowledge! A small [amount of knowledge arouses] a lesser love. A greater amount of knowledge arouses a greater love.
Therefore, it is necessary for a person to seclude himself in order to understand and conceive wisdom and concepts which make his creator known to him according to the potential which man possesses to understand and comprehend as we explained in Hilchot Yesodei HaTorah.

הלכה ז
(נגמר ספר ראשון והוא ספר המדע.)
כסף משנה
7.
(The first book has been completed and it is the Book of Knowledge.)

מדע הלכות תשובה פרק י
Madda Teshuvah Chapter 10