Ituura rir kanono ritituhagia kahiu
The village, which has got a whetstone, does not blunt the knife
The sense of the proverb is that if in a village there is a good whetstone it does not mean that the villagers should purposely blunt their tools in order to whet them. The time will come when the shetstone will have to be used.
Every thing is good in its season.