וּשְׂמַחְתֶּ֗ם לִפְנֵי֮ יְהוָ֣ה אֱלֹֽהֵיכֶם֒ אַתֶּ֗ם וּבְנֵיכֶם֙ וּבְנֹ֣תֵיכֶ֔ם וְעַבְדֵיכֶ֖ם וְאַמְהֹתֵיכֶ֑ם וְהַלֵּוִי֙ אֲשֶׁ֣ר בְּשַֽׁעֲרֵיכֶ֔ם כִּ֣י אֵ֥ין ל֛וֹ חֵ֥לֶק וְנַחֲלָ֖ה אִתְּכֶֽם׃
Sifrei Devarim
(Devarim 12:12) "And you shall rejoice": It is written here "rejoicing," and, elsewhere (27:7) "rejoicing." Just as the "rejoicing" there is with peace-offerings, so, the "rejoicing" here.