הִשָּׁ֣מֶר לְךָ֔ פֶּֽן־תַּעֲזֹ֖ב אֶת־הַלֵּוִ֑י כָּל־יָמֶ֖יךָ עַל־אַדְמָתֶֽךָ׃ (ס)
Take heed to thyself that thou forsake not the Levite as long as thou livest upon thy land.
Sefer HaChinukh
To not forsake the Levite, from giving him his gifts: That we have been warned from forsaking the Levites and not to be negligent from filling their portion - meaning to say to not delay their tithes - and all the more so on festivals, as we are warned about them even more, in order to gladden them at the appointed time. And about this is it stated (Deuteronomy 12:19), "Be careful for yourself, lest you forsake the Levite, all of your days upon your land."