I might think, on Channukah; it is, therefore, written (here) "the end," and, elsewhere (Ibid. 31:10) "the end." Just as "the end" there is a festival, so, "the end" here.
— But, perhaps, just as "the end" there is the festival of Succoth, so, "the end" here; it is, therefore, written "when you finish tithing" — the festival when the tithing has ended, i.e., Pesach. From here they ruled: On the eve of the last day of the Pesach festival of the fourth year and of the seventh year (of the shemitah), there was removal (of the tithe from the house). On the fourth year, by reason of the poor-tithe of the third year; on the seventh year, by reason of the poor-tithe of the sixth year.