Leviticus 27:30-34

(30) All tithes from the land, whether seed from the ground or fruit from the tree, are יהוה’s; they are holy to יהוה. (31) If any party wishes to redeem any tithes, one-fifth must be added to them. (32) All tithes of the herd or flock—of all that passes under the shepherd’s staff, every tenth one—shall be holy to יהוה. (33) One must not look out for good as against bad, or make substitution for it. If one does make substitution for it, then it and its substitute shall both be holy: it cannot be redeemed. (34) These are the commandments that יהוה gave Moses for the Israelite people on Mount Sinai.

ויקרא כ״ז:ל׳-ל״ד

(ל) וְכׇל־מַעְשַׂ֨ר הָאָ֜רֶץ מִזֶּ֤רַע הָאָ֙רֶץ֙ מִפְּרִ֣י הָעֵ֔ץ לַיהֹוָ֖ה ה֑וּא קֹ֖דֶשׁ לַֽיהֹוָֽה׃ (לא) וְאִם־גָּאֹ֥ל יִגְאַ֛ל אִ֖ישׁ מִמַּֽעַשְׂר֑וֹ חֲמִשִׁית֖וֹ יֹסֵ֥ף עָלָֽיו׃ (לב) וְכׇל־מַעְשַׂ֤ר בָּקָר֙ וָצֹ֔אן כֹּ֥ל אֲשֶׁר־יַעֲבֹ֖ר תַּ֣חַת הַשָּׁ֑בֶט הָֽעֲשִׂירִ֕י יִֽהְיֶה־קֹּ֖דֶשׁ לַֽיהֹוָֽה׃ (לג) לֹ֧א יְבַקֵּ֛ר בֵּֽין־ט֥וֹב לָרַ֖ע וְלֹ֣א יְמִירֶ֑נּוּ וְאִם־הָמֵ֣ר יְמִירֶ֔נּוּ וְהָֽיָה־ה֧וּא וּתְמוּרָת֛וֹ יִֽהְיֶה־קֹּ֖דֶשׁ לֹ֥א יִגָּאֵֽל׃ (לד) אֵ֣לֶּה הַמִּצְוֺ֗ת אֲשֶׁ֨ר צִוָּ֧ה יְהֹוָ֛ה אֶת־מֹשֶׁ֖ה אֶל־בְּנֵ֣י יִשְׂרָאֵ֑ל בְּהַ֖ר סִינָֽי׃

Taanit 8b:14

The Sages taught: One who enters to measure produce in his granary recites: May it be Your will, Adonai our God, that You send a blessing upon the work of our hands. After he has begun to measure, he recites: Blessed is the one who sends a blessing upon this pile. If one first measured and afterward recited the blessing, it is a prayer in vain, as a blessing is not found either in an object that is weighed or in an object that is measured or in an object that is counted, as these would constitute open miracles. Rather, a blessing is found only in an object that is hidden from the eye.

תענית ח׳ ב:י״ד

תָּנוּ רַבָּנַן: הַנִּכְנָס לָמוֹד אֶת גׇּרְנוֹ, אוֹמֵר: ״יְהִי רָצוֹן מִלְּפָנֶיךָ ה׳ אֱלֹהֵינוּ שֶׁתִּשְׁלַח בְּרָכָה בְּמַעֲשֵׂה יָדֵנוּ״. הִתְחִיל לָמוֹד, אוֹמֵר: ״בָּרוּךְ הַשּׁוֹלֵחַ בְּרָכָה בַּכְּרִי הַזֶּה״. מָדַד וְאַחַר כָּךְ בֵּירַךְ — הֲרֵי זוֹ תְּפִלַּת שָׁוְא, לְפִי שֶׁאֵין הַבְּרָכָה מְצוּיָה לֹא בְּדָבָר הַשָּׁקוּל, וְלֹא בְּדָבָר הַמָּדוּד, וְלֹא בְּדָבָר הַמָּנוּי, אֶלָּא בְּדָבָר הַסָּמוּי מִן הָעַיִן.