Exodus 16:18, 33, 36

When they measured it with an omer, he who had gathered much had no excess, and he who had gathered little had no lack; every man gathered as much as he should eat.

Moses said to Aaron, “Take a jar and put an omerful of manna in it, and place it before the LORD to be kept throughout your generations.”

(Now an omer is a tenth of an ephah.)