Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 131
The full Hebrew text of Mishneh Torah, Positive Mitzvot, Chapter 131, with English translation by Maimonides (Rambam).
להתוודות וידוי מעשר, שנאמר: "ואמרת לפני ה' אלוהיך ביערתי הקודש" (דברים כו,יג).
To give thanks, [reciting] the declaration concerning the tithes, as [Deuteronomy 26:13] states: "And you shall declare before God, your Lord, `I have removed the sacred [foods]...."'