Most people know that the Biblical meaning of a word is determined by its underlying three-letter root. The Biblical root can be conjugated in different a) persons, b) tenses, c) pluralities, d) genders, e) constructions and f) modalities. For example I watched has a different conjugation then I will be watched even though both phrases will use the same 3 letter Hebrew root.

Additionally, a three letter root can take on new meaning based on the connective preposition used with it. For example the Hebrew root Tzade-Vav-Hey can mean to command someone, or, to delegate someone to speak to others. How does one tell which meaning applies in a given verse? Rashi explains when this root is used with the Hebrew connective, Aleph-Lamed, El which means to the verb-connective pair of words means to delegate someone else to speak to the target person Hence the Rashi-suggested translation of verse Ex50-16a which states And delegated [someone] to Joseph, saying, Your father did command before he died, saying,

Advanced Rashi: Actually Rashi simply cites other verses where Tzivah el means delegate. The idea of explicitly associating every verb-preposition pair with a distinct meaning is made explicit by the Malbim in his Morning hind.