Manna was a mysterious food that, according to the Bible, appeared each morning on the ground to feed the Israelites during their 40 years wandering in the desert after escaping slavery in Egypt. The Bible describes it as white, flaky, and tasting like honey wafers. Each day people would gather just enough for that day (except before the Sabbath, when they could collect a double portion), and any extra would spoil by morning.

The story says the Israelites had no idea what this strange substance was. When they first saw it covering the ground, they asked each other what it was in confusion, and the name stuck.

Today, people use manna to describe any unexpected help that arrives exactly when you need it most. If your family is struggling to pay bills and suddenly receives an unexpected gift of money, someone might call it manna from heaven. When you're stuck on a difficult homework problem and a friend explains it perfectly, that explanation is like manna. The phrase captures that feeling of relief when help appears just when you thought you were out of options.