After two whole years, Pharaoh dreamed that he was standing by the Nile, and behold, there came up out of the Nile seven cows, attractive and plump, and they fed in the reed grass.
Genesis 41:1-2

The Egyptians look down to the River for their sustenance, but the River didn't care about them. The Hebrews look up to Heaven, which cared about them very much. An interesting contrast.

In Pharaoh's dream, the cows all came out of the river and the plump and thin ears of grain all grew on a single stalk. Egypt was dependent on a single source for all their prosperity: the Nile. There are both spiritual and economic lesson here.

1) Put your trust in Heaven, not in things on earth.
2) Don't put all your material eggs in one basket.