Today's Rashi deals with tenses. Most people know that verbs can indicate action in specific periods of time such as future e.g. I will eat the apple, past e.g. I ate the apple, and present e.g. I am eating the apple. The present itself has several forms such as simple present e.g. I am eating the apple, habitual present e.g. I eat an apple every day, informational present e.g. To avoid sickness I eat an apple. Both the past and future can also have habitual and progressive and informational forms.

We must carefully distinguish between meaning and conjugation. The last paragraph enumerated close to a dozen types of meanings associated with verbs. But there are only 3 major conjugations associated with verbs. Consequently the grammarian must learn how to select conjugations that indicate meaning. Furthermore, since there are more meanings than conjugations it follows that the same conjugation can mean different things.

Rashi translates Ex01-12b discussing the abuse of the Jews And as they [the Egyptians] abused him [the Jews] so he [keeps on] multiplys[ing] and expands.... In this sentence the sense of the phrase so he multiplies... is continuous action that happened in the past, is happening at the time of the abuse and will happen in the future. In other words the meaning of the verse is habitual.

We now understand the Rashi: The verse uses a future conjugation to indicate the habitual. Here Rashi is explaining that the future conjugation besides being used to indicate a future meaning can also be used to indicate the habitual meaning.

Here is yet a simpler way to understand Rashi: You are not obligated to translate the verse as as they abused him so he will multiply and expand. It is best to translate the verse as they abused him so he multiplys and expands. This has the same sense as a as they abused him so he keeps on multiplying and keeps on expanding.