In the final preparations to leave Egypt,
This request comes after a period of three days of darkness so thick that the Egyptians were completely immobilized. They were at the mercy of the Jews, who were graced with light and mobility. For three days, all of the Egyptians’ possessions were in plain view, unprotected in their homes. But despite their impoverished state, and temptation to take revenge for all the horrors inflicted on them by their former taskmasters, not a single Jew took advantage of the situation. Not one touched an Egyptian or even the least of his possessions. When they emerged from the darkness, the Egyptians were in disbelief that their possessions were in order and unscathed. The people had proven their moral worth in the most brilliant and astounding manner.
Here, the Torah tells us G-d let Egypt see that the people was worthy of favor. By revealing their impeccable character, generations of antipathy and stereotypes were eradicated. At this moment, they were struck by the moral nobility of the people they had mistreated for so many years.
It is no wonder, then, that Moshe and the people were reluctant to compromise this moral victory by requesting from the Egyptians the very possessions which they dared not touch without permission. They needed to be persuaded and urged to ask for these gifts. Nevertheless,
Sources: Commentary Shemot 11:2-3