Agwata ma tek mac aye puku

Hardened gourd is softened by fire.

What it means
A gourd gone hard and brittle won't bend for anything gentle; only real heat softens it. People can be like that too: sometimes understanding only comes after something truly hard forces it.
Acholi · East Africa
Source and context
From: Acholi, East Africa
Source: Acholi (Uganda, South Sudan) proverb; original text, translation and explanation from "Acholi Proverbs: (118 in Total)," African Manners (africanmanners.wordpress.com), 2012. Earlier recorded here as documented in "Caro lok: proverbs & wise sayings of the Acoli people of Uganda"; that book was not read.

The source explains it: used of a person who needs tough treatment before he can see sense. The wording of the meaning is ours.