When the Israelites finally left Egypt, they did not leave empty-handed. The Torah describes them departing with "flocks and herds, a great crush of cattle" — a staggering procession of wealth streaming out of the land that had enslaved them for generations.
The Mekhilta connects this moment directly to a promise God made to Abraham centuries earlier. In the famous Covenant Between the Pieces (Genesis 15:14), God told Abraham that his descendants would be enslaved in a foreign land — but that afterward, "they will go out with great wealth." The rabbis understood this to mean that God was making a binding commitment: at the moment of the exodus, He would fill the Israelites with silver and gold.
This teaching transforms the Exodus from a story of mere escape into a story of divine compensation. The Israelites were not refugees fleeing with whatever they could grab. They were recipients of a debt that had been accruing for four hundred years. Every flock, every herd, every piece of precious metal they carried out of Egypt was a fulfillment of the oldest promise in their national memory.
The rabbis saw in this a fundamental principle about how God operates in history. Suffering is never the final chapter. The same God who foretold the slavery also foretold the wealth. The "great crush of cattle" was not an accident of history — it was the second half of a sentence that began with Abraham.