Sources for Zohar 1:155b "Reuben went and found mandrakes in the field"
(יד) וַיֵּ֨לֶךְ רְאוּבֵ֜ן בִּימֵ֣י קְצִיר־חִטִּ֗ים וַיִּמְצָ֤א דֽוּדָאִים֙ בַּשָּׂדֶ֔ה וַיָּבֵ֣א אֹתָ֔ם אֶל־לֵאָ֖ה אִמּ֑וֹ וַתֹּ֤אמֶר רָחֵל֙ אֶל־לֵאָ֔ה תְּנִי־נָ֣א לִ֔י מִדּוּדָאֵ֖י בְּנֵֽךְ׃
(14) Once, at the time of the wheat harvest, Reuben came upon some mandrakes in the field and brought them to his mother Leah. Rachel said to Leah, “Please give me some of your son’s mandrakes.”
(כד) מָֽה־רַבּ֬וּ מַעֲשֶׂ֨יךָ ׀ יי כֻּ֭לָּם בְּחָכְמָ֣ה עָשִׂ֑יתָ מָלְאָ֥ה הָ֝אָ֗רֶץ קִנְיָנֶֽךָ׃
(24) How many are the things You have made, O LORD; You have made them all with wisdom; the earth is full of Your creations.
(ו) בִּדְבַ֣ר יי שָׁמַ֣יִם נַעֲשׂ֑וּ וּבְר֥וּחַ פִּ֝֗יו כָּל־צְבָאָֽם׃
(6) By the word of the LORD the heavens were made, by the breath of His mouth, all their host.
(טו) וַתֹּ֣אמֶר לָ֗הּ הַמְעַט֙ קַחְתֵּ֣ךְ אֶת־אִישִׁ֔י וְלָקַ֕חַת גַּ֥ם אֶת־דּוּדָאֵ֖י בְּנִ֑י וַתֹּ֣אמֶר רָחֵ֗ל לָכֵן֙ יִשְׁכַּ֤ב עִמָּךְ֙ הַלַּ֔יְלָה תַּ֖חַת דּוּדָאֵ֥י בְנֵֽךְ׃
(15) But she said to her, “Was it not enough for you to take away my husband, that you would also take my son’s mandrakes?” Rachel replied, “I promise, he shall lie with you tonight, in return for your son’s mandrakes.”
(יד) הַֽדּוּדָאִ֣ים נָֽתְנוּ־רֵ֗יחַ וְעַל־פְּתָחֵ֙ינוּ֙ כָּל־מְגָדִ֔ים חֲדָשִׁ֖ים גַּם־יְשָׁנִ֑ים דּוֹדִ֖י צָפַ֥נְתִּי לָֽךְ׃
(14) The mandrakes yield their fragrance, At our doors are all choice fruits; Both freshly picked and long-stored Have I kept, my beloved, for you.
(כב) וַיִּזְכֹּ֥ר אֱלֹקִ֖ים אֶת־רָחֵ֑ל וַיִּשְׁמַ֤ע אֵלֶ֙יהָ֙ אֱלֹקִ֔ים וַיִּפְתַּ֖ח אֶת־רַחְמָֽהּ׃
(22) Now God remembered Rachel; God heeded her and opened her womb.
(טז) וַיָּבֹ֨א יַעֲקֹ֣ב מִן־הַשָּׂדֶה֮ בָּעֶרֶב֒ וַתֵּצֵ֨א לֵאָ֜ה לִקְרָאת֗וֹ וַתֹּ֙אמֶר֙ אֵלַ֣י תָּב֔וֹא כִּ֚י שָׂכֹ֣ר שְׂכַרְתִּ֔יךָ בְּדוּדָאֵ֖י בְּנִ֑י וַיִּשְׁכַּ֥ב עִמָּ֖הּ בַּלַּ֥יְלָה הֽוּא׃
(16) When Jacob came home from the field in the evening, Leah went out to meet him and said, “You are to sleep with me, for I have hired you with my son’s mandrakes.” And he lay with her that night.
(יח) בָּרִאשֹׁ֡ן בְּאַרְבָּעָה֩ עָשָׂ֨ר י֤וֹם לַחֹ֙דֶשׁ֙ בָּעֶ֔רֶב תֹּאכְל֖וּ מַצֹּ֑ת עַ֠ד י֣וֹם הָאֶחָ֧ד וְעֶשְׂרִ֛ים לַחֹ֖דֶשׁ בָּעָֽרֶב׃
(18) In the first month, from the fourteenth day of the month at evening, you shall eat unleavened bread until the twenty-first day of the month at evening.

(ג) לֹא־תֹאכַ֤ל עָלָיו֙ חָמֵ֔ץ שִׁבְעַ֥ת יָמִ֛ים תֹּֽאכַל־עָלָ֥יו מַצּ֖וֹת לֶ֣חֶם עֹ֑נִי כִּ֣י בְחִפָּז֗וֹן יָצָ֙אתָ֙ מֵאֶ֣רֶץ מִצְרַ֔יִם לְמַ֣עַן תִּזְכֹּר֔ אֶת־י֤וֹם צֵֽאתְךָ֙ מֵאֶ֣רֶץ מִצְרַ֔יִם כֹּ֖ל יְמֵ֥י חַיֶּֽיךָ׃

(3) You shall not eat anything leavened with it; for seven days thereafter you shall eat unleavened bread (מַצּ֖וֹת), bread of distress (לֶ֣חֶם עֹ֑נִי)—for you departed from the land of Egypt hurriedly—so that you may remember the day of your departure from the land of Egypt as long as you live.

(יא) כִּ֚י הַמִּצְוָ֣ה הַזֹּ֔את אֲשֶׁ֛ר אָנֹכִ֥י מְצַוְּךָ֖ הַיּ֑וֹם לֹֽא־נִפְלֵ֥את הִוא֙ מִמְּךָ֔ וְלֹ֥א רְחֹקָ֖ה הִֽוא׃

(11) Surely, this Instruction (הַמִּצְוָ֣ה) which I enjoin upon you this day is not too baffling for you, nor is it beyond reach.

(ה) אֶ֗רֶץ מִמֶּ֥נָּה יֵֽצֵא־לָ֑חֶם וְ֝תַחְתֶּ֗יהָ נֶהְפַּ֥ךְ כְּמוֹ־אֵֽשׁ׃
(5) Earth, out of which food grows, Is changed below as if into fire.
(ד) וַיֹּ֤אמֶר יי אֶל־מֹשֶׁ֔ה הִנְנִ֨י מַמְטִ֥יר לָכֶ֛ם לֶ֖חֶם מִן־הַשָּׁמָ֑יִם וְיָצָ֨א הָעָ֤ם וְלָֽקְטוּ֙ דְּבַר־י֣וֹם בְּיוֹמ֔וֹ לְמַ֧עַן אֲנַסֶּ֛נּוּ הֲיֵלֵ֥ךְ בְּתוֹרָתִ֖י אִם־לֹֽא׃
(4) And the LORD said to Moses, “I will rain down bread for you from the sky, and the people shall go out and gather each day that day’s portion—that I may thus test them, to see whether they will follow My instructions or not.
(יד) יִשָּׂשכָ֖ר חֲמֹ֣ר גָּ֑רֶם רֹבֵ֖ץ בֵּ֥ין הַֽמִּשְׁפְּתָֽיִם׃
(14) Issachar is a strong-boned ass, Crouching among the sheepfolds.
(ט) מֽוֹשִׁיבִ֨י ׀ עֲקֶ֬רֶת הַבַּ֗יִת אֵֽם־הַבָּנִ֥ים שְׂמֵחָ֗ה הַֽלְלוּ־יָֽהּ׃

(9) He sets the childless woman among her household as a happy mother of children. Hallelujah.

Zohar, 1:158a

From here we learn that whoever engages in Torah inherits both the world that is coming and the inheritance of Jacob. He inherits the world that is coming, as it is written Yissachar, yesh sakhar, Issachar-there is reward; similarly, So I may endow those who love Me with yesh, substance, and fill their treasuries (Proverbs 8:21)