Hesabu 19 : 19 Numbers chapter 19 verse 19

na yule aliye safi atamnyunyiza huyo aliye najisi siku ya tatu, na siku ya saba; na katika siku ya saba atamtakasa; naye atazifua nguo zake, na kuoga majini, naye atakuwa safi jioni.
soma Mlango wa 19

and the clean person shall sprinkle on the unclean on the third day, and on the seventh day: and on the seventh day he shall purify him; and he shall wash his clothes, and bathe himself in water, and shall be clean at even.