The Torah tells us (Shemos 15:22 ) that Moshe guided the people from the Red Sea to the wilderness. Rashi comments that Moshe took them against their will. This was because the now drowned Egyptian horses had been adorned with gold, silver, and precious stones which the Jews found on the shore. Indeed, these riches, Rashi says, were greater than those with which the Jewish people left Egypt, and they wanted to stay and collect them.

The Talmud tells us in Berachos that before the exodus from Egypt, G-d begged Moshe to motivate Bnei Yisrael to collect gold and silver from the Egyptians. In this way, He would be fulfilling his promise to Avraham that the Jews would leave Egypt with riches.

If, as Rashi says, there was so much gold and silver available in the Red Sea after the drowning of the Egyptians, why was G-d so concerned that the promise to Avraham for wealth would be fulfilled as the Jews were leaving Egypt? Why did he have to beg Moshe to ensure its fulfillment just before the exodus, when in fact the people would later have the opportunity to gather riches from the sea that were of even greater value?

The Dubno Maggid offered the following parable to answer this problem. There were once two kings who had a dispute regarding a piece of territory along the border which their two countries shared. They knew that if they went to war against one another and sent their armies into battle, it would result in a great loss of life. Instead, they each agreed to choose a champion who would represent their nations in a single, man-to-man battle and the disputed territory would go to the winner. As the two, evenly-matched champions fought one another, one gained the advantage and lifted the other above his head, about to hurl him into a deep pit in which he would surely be killed. Suddenly and unexpectedly, the warrior who was about to lose his life broke free and threw his opponent into the pit. The winning king congratulated his champion, but nonetheless informed him that he would be punished. "Why?" he asked, "did I not bring victory to my king?" The king responded: "It is true that you were victorious in your battle and that you did your king a great service. But during those moments when your adversary was winning and it seemed as if you would be killed, you caused me to suffer great fear and anxiety that I would lose the territory for which you were fighting. And that anxiety was no small thing. For that you must be punished."

So too, explained the Dubno Maggid. Not only did G-d wish to fulfill His promise to Avraham, but he wanted to do it in a way that Avraham would have no anxiety. Indeed, G-d could have waited to deliver the "great wealth" to Avraham until the miracle at the sea. But the journey from Egypt to the sea was seven days. And G-d didn't want Avraham to suffer any distress or anxiety regarding the fulfillment of the promise even if it was only seven days.