Exodus 3:21 New English Translation

²¹“I will grant this people favor with^[a] the Egyptians, so that when^[b] you depart you will not leave empty-handed.

Exodus 3:21 tn Heb “in the eyes of.” This idiom usually means that someone will be treated well by the observer. It is unlikely that it means here that the Egyptians will like the Hebrews. Rather, it means that the Egyptians will give things to the Hebrews free—gratis (see 12:35-36). Not only will God do mighty works to make the king yield, but also he will work in the minds of the Egyptian people so that they will be favorably disposed to give Israel wealth.
Exodus 3:21 tn The temporal indicator (here future) with the particle ki (וְהָיָה כִּי, v^ehaya ki) introduces a temporal clause.

New English Translation (NET)