Before the conflict with Pharaoh, God had said to Moses:

"I will give this people favour in the sight of the Egyptians and it shall come to pass that when ye go ye shall not go empty, but every woman shall borrow of her neighbor and of her that sojourneth in her house jewels of silver and jewels of gold and raiment and ye shall put them upon your sons and upon your daughters and ye shall spoil the Egyptians."
.............................Exodus 3:21-22