From: Bemba, Southern Africa
Source: Bemba (Zambia) proverb (IFYAKULYA UBUSHIKU FITULIKILA KUMALUSHI); translation and explanation from "Bemba Proverbs And Their Role In Society," The Zambian Observer (zambianobserver.com). Earlier recorded here as also in Laur Mwepu Luiza, "A Collection of 100 Bemba Proverbs" (afriprov.tangaza.ac.ke); that collection was not re-read.
The source explains it: secret deeds cannot remain hidden forever
. The wording of the meaning is ours.