Halakhah zu Dewarim 12:19

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."