Regarding watchfulness and guarding of one's thoughts, it is proper that you do not neglect watching over your thoughts, reflections, and musings of your heart. For most of the deterioration and rectification in deeds is due to nothing else but these and varies according to their deterioration and rectification.
As the verses say: "Guard your heart above all else, for it determines the course of your life" (Mishlei 4:23), and "for the imagination of man's heart is evil from his youth" (Bereishis 8:21), "For I know their imagination.." (Devarim 31:21), "for the L-rd searches all hearts, and He understands all the imaginations of the thoughts of every creation; [if you seek Him, He will be found to you, and if you forsake Him, He will abandon you forever]" (Divrei Hayamim 28:9), "Rather,[this] thing is very close to you; it is in your mouth and in your heart, so that you may do it" (Devarim 30:14), "And now, O Israel, what does the L-rd, your G-d, demand of you? Only to fear (revere) the L-rd, your G-d" (Devarim 10:12), and fear (reverence) is in the heart, reflections, and thoughts. Therefore, my brother, strive that all of your actions be devoted only to the blessed Creator, so that your exertion will not be for nothing, and your efforts not for falsehood, as written "Why should you weigh out money for that which is not bread and your toil without satiety?" (Yeshaya 55:2).
Do not neglect what I have aroused you to. For I have collected for you in this gate all the roots of the things detrimental to activities devoted to G-d, and from each root sprouts almost endless branches.
Therefore, you must guard from them to the utmost of your ability. Maybe then your acts will be complete before G-d and devoted wholeheartedly to His Name, and will then be pleasing and receive acceptance from the Creator. Conduct yourself in the service of G-d as you conduct yourself in your worldly affairs, where you choose the best option you can find and which will be far from potential damages, clean from falsehood, and clean of confusions. Since you do all this for this fleeting world, all the more so that you should do this many times over for matters of your final, permanent existence, and for what will bring you closer to G-d.
Strive with all of your strength that your deeds be pure even though they will be fewer. For it is better than if you exert yourself to do many acts which are not pure. Because a small amount of pure is much, while a large amount of not pure is little and useless. And all the more so, that your work, small and insignificant as it is, should not be impure before G-d.
Be careful that the matter of your deeds to G-d won't be like that of a certain careless bird which the verse speaks of, which lays an egg on the ground and sits on it to warm it, whereby other living creatures damage the egg and no chick hatches from it, as the verse says: "For she leaves her eggs on the ground, and she warms herself on the earth. She forgets that a foot may crush them, and the beast of the field may trample them. [She is hardened against her young ones as though they were not hers; though her toil is in vain, she has no fear]" (Iyov 39:13-16), and the rest of the matter.
The wise man already praised a creature who has the opposite trait. It is industrious and hardworking for its interests in this world. He commanded us to observe it and learn from it, even though it is the weakest of the vermin, saying:
"Go to the ant, lazy one! observe its ways and become wise; she prepares her bread in the summer; [for she has no chief, overseer, or ruler; she gathers her food in the harvest. O lazy one, how long will you lie there; when will you get up from your sleep?]" (Mishlei 6:6-9)
Behold, we have discussed a small part of a large matter. Let it not seem excessive in your eyes, and don't be discouraged by it. For according to the value and importance of a matter will be the corresponding potentially detrimental things.
The value and importance of our investigation in this book is not unknown by he who understands. May G-d, in His mercy, place our portion among those who are complete with Him, and who endeavor for the sake of His great Name, Amen.
אֲבָל הַזְּהִירוּת בַּמַּחֲשָׁבָה וּשְׁמִירָתָהּ רָאוּי לְךָ שֶׁלֹּא תִּתְעַלֵּם לִפְקוֹד מַחְשַׁבְתְּךָ וְרַעְיוֹנֶיךָ וְשַׂרְעַפֵּי לִבְּךָ כִּי רֹב הַהֶפְסֵד וְהַתִּקּוּן בַּמַּעֲשִׂים לֹא יִהְיֶה כִּי אִם מֵחֲמָתָם כְּפִי תִּקּוּנָם וְהֶפְסֵדָם.
Regarding watchfulness and guarding of one's thoughts, it is proper that you do not neglect watching over your thoughts, reflections, and musings of your heart. For most of the deterioration and rectification in deeds is due to nothing else but these and varies according to their deterioration and rectification.
כְּמוֹ שֶׁאָמַר הַכָּתוּב (משלי ד) מִכָּל מִשְׁמָר נְצֹר לִבֶּךָ כִּי מִמֶּנּוּ תּוֹצְאוֹת חַיִּים וְאָמְרָה תּוֹרָה (בראשית ח׳:כ״א) כִּי יֵצֶר לֵב הָאָדָם רַע מִנְּעֻרָיו וְאָמַר (דברים לא) כִּי יָדַעְתִּי אֶת יִצְרוֹ וְאָמַר (ד״ה א כח) כִּי כָל לְבָבוֹת דּוֹרֵשׁ ה׳ וְכָל יֵצֶר מַחֲשָׁבוֹת מֵבִין וְאָמַר (דברים ל) כִּי קָרוֹב אֵלֶיךָ הַדָּבָר מְאֹד בְּפִיךָ וּבִלְבָבְךָ לַעֲשֹׂתוֹ וְאָמַר (שם י) מָה ה׳ אֱלֹהֶיךָ שֹׁאֵל מֵעִמָּךְ כִּי אִם לְיִרְאָה וְהַיִּרְאָה אֵינָהּ אֶלָּא בַּלֵּב וְהָרַעֲיוֹן וְהַמַּחְשָׁבָה, וְעַל כֵּן יֵשׁ לְךָ אָחִי לְהִשְׁתַּדֵּל לִהְיוֹת כָּל מַעֲשֶׂיךָ מְיֻחָדִים לַבּוֹרֵא יִתְבָּרַךְ וְאַל יִהְיֶה עֲמָלְךָ לָרִיק וְטָרְחֲךָ לַשֶּׁקֶר כמ״ש (ישעיהו נ״ה:ב׳) לָמָּה תִשְׁקְלוּ כֶסֶף בְּלוֹא לֶחֶם וְגוֹ׳,
As the verses say: "Guard your heart above all else, for it determines the course of your life" (Mishlei 4:23), and "for the imagination of man's heart is evil from his youth" (Bereishis 8:21), "For I know their imagination.." (Devarim 31:21), "for the L-rd searches all hearts, and He understands all the imaginations of the thoughts of every creation; [if you seek Him, He will be found to you, and if you forsake Him, He will abandon you forever]" (Divrei Hayamim 28:9), "Rather,[this] thing is very close to you; it is in your mouth and in your heart, so that you may do it" (Devarim 30:14), "And now, O Israel, what does the L-rd, your G-d, demand of you? Only to fear (revere) the L-rd, your G-d" (Devarim 10:12), and fear (reverence) is in the heart, reflections, and thoughts. Therefore, my brother, strive that all of your actions be devoted only to the blessed Creator, so that your exertion will not be for nothing, and your efforts not for falsehood, as written "Why should you weigh out money for that which is not bread and your toil without satiety?" (Yeshaya 55:2).
וְאַל תִּתְעַלֵּם מִמָּה שֶׁהַעִירוֹתִיךָ עָלָיו כִּי כְּבָר קִבַּצְתִּי לְךָ בַּשַּׁעַר הַזֶּה כָּל שָׁרְשֵׁי מַפְסִידֵי הַמַּעֲשִׂים הַמְיֻחָדִים לֵאלֹהִים, וְתַחַת כָּל שֹׁרֶשׁ מֵהֶם עֲנָפִים כִּמְעַט שֶׁאֵין לָהֶם קֵץ,
Do not neglect what I have aroused you to. For I have collected for you in this gate all the roots of the things detrimental to activities devoted to G-d, and from each root sprouts almost endless branches.
עַל כֵּן אַתָּה צָרִיךְ לְהִשָּׁמֵר מֵהֶם בְּכָל יְכָלְתְּךָ אוּלַי יִהְיֶה מַעַשְׂךָ שָׁלֵם לֵאלֹהִים וּמְיֻחָד לִשְׁמוֹ וְיִהְיֶה רָצוּי וּמְקֻבָּל אֵצֶל הַבּוֹרֵא קִבּוּל טוֹב. וּנְהוֹג בּוֹ מִנְהָגְךָ כְּעִנְיְנֵי עוֹלָמְךָ כִּי אַתָּה חוֹשֵׁב עַל הַטּוֹב שֶׁתִּמְצָא בְּמִינֵיהֶם וַאֲשֶׁר יִהְיֶה רָחוֹק מִן הַפְּגָעִים בָּהֶם וּמְנֻקֶּה מִן הַזִּיּוּף וְזַךְ מִן הַבִּלְבּוּל, וְכֵיוָן שֶׁאַתָּה עוֹשֶׂה זֶה בְּעִנְיְנֵי עוֹלָמְךָ הַכָּלֶה כָּל שֶׁכֵּן שֶׁתַּעֲשֶׂה כִּפְלַיִם בְּעִנְיְנֵי אַחֲרִיתְךָ הַקַּיֶּמֶת וּבְמָה שֶׁתִּתְקָרֵב בּוֹ אֶל הָאֱלֹהִים.
Therefore, you must guard from them to the utmost of your ability. Maybe then your acts will be complete before G-d and devoted wholeheartedly to His Name, and will then be pleasing and receive acceptance from the Creator. Conduct yourself in the service of G-d as you conduct yourself in your worldly affairs, where you choose the best option you can find and which will be far from potential damages, clean from falsehood, and clean of confusions. Since you do all this for this fleeting world, all the more so that you should do this many times over for matters of your final, permanent existence, and for what will bring you closer to G-d.
וְהִשְׁתַּדֵּל בְּכֹחֲךָ לְזַכֵּךְ מַעֲשֶׂיךָ וְאִם יִמְעַט יוֹתֵר מִמָּה שֶׁתִּשְׁתַּדֵּל שֶׁיִּהְיֶה רַב בִּלְתִּי זַךְ כִּי הַמְּעַט הַזַּךְ הוּא רַב וְהָרַב בִּלְתִּי זַךְ הוּא מְעַט וְאֵין בּוֹ תּוֹעֶלֶת וכ״ש שֶׁיִּהְיֶה מַעַשְׂךָ עִם מִעוּטוֹ וּזְעִירוּתוֹ בִּלְתִּי זַךְ לֵאלֹהִים.
Strive with all of your strength that your deeds be pure even though they will be fewer. For it is better than if you exert yourself to do many acts which are not pure. Because a small amount of pure is much, while a large amount of not pure is little and useless. And all the more so, that your work, small and insignificant as it is, should not be impure before G-d.
וְהִזָּהֵר שֶׁלֹּא יִהְיֶה עִנְיָנְךָ בְּמַעֲשֶׂיךָ לֵאלֹהִים כְּעִנְיַן הָעוֹף שֶׁאָמַר עָלֶיהָ הַכָּתוּב שֶׁהִיא יוֹלֶדֶת הַבֵּיצָה וּמְחַמֶּמֶת אוֹתָהּ עַל פְּנֵי הָאָרֶץ מִמִּעוּט שְׁמִירָתָהּ אוֹתָהּ עַד שֶׁיַּפְסִידוּהָ שְׁאָר בַּעֲלֵי חַיִּים וְלֹא תַעֲשֶׂה אֶפְרוֹחַ כְּמוֹ שֶׁאָמַר הַכָּתוּב (איוב לט) כְּנַף רְנָנִים נֶעֱלָסָה וְגוֹ׳ כִּי תַעֲזֹב לָאָרֶץ בֵּצֶיהָ וְעַל עָפָר תְּחַמֵּם וַתִּשְׁכַּח כִּי רֶגֶל תְּזוּרֶהָ וּשְׁאָר הָעִנְיָן,
Be careful that the matter of your deeds to G-d won't be like that of a certain careless bird which the verse speaks of, which lays an egg on the ground and sits on it to warm it, whereby other living creatures damage the egg and no chick hatches from it, as the verse says: "For she leaves her eggs on the ground, and she warms herself on the earth. She forgets that a foot may crush them, and the beast of the field may trample them. [She is hardened against her young ones as though they were not hers; though her toil is in vain, she has no fear]" (Iyov 39:13-16), and the rest of the matter.
וּכְבָר שִׁבֵּחַ הֶחָכָם מִי שֶׁהוּא בְּהֶפֶךְ הָעִנְיָן הַזֶּה בִּזְרִיזוּתוֹ וְהִשְׁתַּדְּלוּתוֹ הַטּוֹבָה בְּעוֹלָמוֹ וְצִוָּנוּ לִבְחֹן בּוֹ וְלִלְמֹד מִמַּעֲשֵׂהוּ וְאִם הוּא חַלָּשׁ שֶׁבָּרְמָשִׂים כְּאָמְרוֹ:
The wise man already praised a creature who has the opposite trait. It is industrious and hardworking for its interests in this world. He commanded us to observe it and learn from it, even though it is the weakest of the vermin, saying:
(משלי ו) לֵךְ אֶל נְמָלָה עָצֵל וְגוֹ׳ תָּכִין בַּקַּיִץ לַחְמָהּ וְגוֹ׳.
"Go to the ant, lazy one! observe its ways and become wise; she prepares her bread in the summer; [for she has no chief, overseer, or ruler; she gathers her food in the harvest. O lazy one, how long will you lie there; when will you get up from your sleep?]" (Mishlei 6:6-9)
וְהִנֵּה זָכַרְנוּ לְךָ מְעַט מֵהַרְבֵּה וְאַל יִרְבֶּה בְּעֵינֶיךָ וְאַל תָּקֹץ בּוֹ כִּי כְּפִי מַעֲלוֹת חֲשִׁיבוּת הַמְּלָאכוֹת יִהְיוּ הַפְּגָעִים הַקּוֹרִים אוֹתָם.
Behold, we have discussed a small part of a large matter. Let it not seem excessive in your eyes, and don't be discouraged by it. For according to the value and importance of a matter will be the corresponding potentially detrimental things.
וּמֶחְקָרֵנוּ בַּסֵּפֶר הַזֶּה אֵין מַעֲלָתוֹ וַחֲשִׁיבוּתוֹ נֶעְלֶמֶת מִמִּי שֶׁמֵּבִין. הָאֱלֹהִים יְשִׂימֵנוּ מִן הַשְּׁלֵמִים עִמּוֹ וְהָעוֹשִׂים לִשְׁמוֹ הַגָּדוֹל בְּרַחֲמָיו אָמֵן:
נִשְׁלַם שַׁעַר הַחֲמִישִׁי. בְּעֶזְרַת אֱלֹהַי קְדֹשִׁי:
The value and importance of our investigation in this book is not unknown by he who understands. May G-d, in His mercy, place our portion among those who are complete with Him, and who endeavor for the sake of His great Name, Amen.