I had a neighbor once tell me that if I wanted our walnut tree to produce more nuts, I should whack it a bunch with a baseball bat or a golf club. This would stress the tree and cause it to produce more fruit/nuts. These verses about how the Egyptians oppressed the children of Israel remind me of what my neighbor said.
“So they put slave masters over them to oppress them with forced labor, and they built Pithom and Rameses as store cities for Pharaoh. But the more they were oppressed, the more they multiplied and spread; so the Egyptians came to dread the Israelites and worked them ruthlessly. They made their lives bitter with harsh labor in brick and mortar and with all kinds of work in the fields; in all their harsh labor the Egyptians worked them ruthlessly.
Exodus 1:11-14 NIV http://bible.com/111/exo.1.11-14.NIV