Numbers 9:2

וְשֵׁרֵת אֶת־אֶחָיו בְּאֹהֶל מוֹעֵד לִשְׁמֹר מִשְׁמֶרֶת וַעֲבֹדָה לֹא יַעֲבֹד כָּכָה תַּעֲשֶׂה לַלְוִיִּם בְּמִשְׁמְרֹתָֽם

but shall minister with their brethren in the tent of meeting, to keep the charge, but they shall do no manner of service. Thus shalt thou do unto the Levites touching their charges.’

וַיְדַבֵּר יְהוָה אֶל־מֹשֶׁה בְמִדְבַּר־סִינַי בַּשָּׁנָה הַשֵּׁנִית לְצֵאתָם מֵאֶרֶץ מִצְרַיִם בַּחֹדֶשׁ הָרִאשׁוֹן לֵאמֹֽר

And the LORD spoke unto Moses in the wilderness of Sinai, in the first month of the second year after they were come out of the land of Egypt, saying:

בְּאַרְבָּעָה עָשָֽׂר־יוֹם בַּחֹדֶשׁ הַזֶּה בֵּין הָֽעֲרְבַּיִם תַּעֲשׂוּ אֹתוֹ בְּמוֹעֲדוֹ כְּכָל־חֻקֹּתָיו וּכְכָל־מִשְׁפָּטָיו תַּעֲשׂוּ אֹתֽוֹ

In the fourteenth day of this month, at dusk, ye shall keep it in its appointed season; according to all the statutes of it, and according to all the ordinances thereof, shall ye keep it.’

וַיְדַבֵּר מֹשֶׁה אֶל־בְּנֵי יִשְׂרָאֵל לַעֲשֹׂת הַפָּֽסַח

And Moses spoke unto the children of Israel, that they should keep the passover.