A very common special verb construction
In lesson 2, We saw how a ו + perfect could create a sequential-perfect construction in which the aspect is flipped to imperfect and a further step in the sequence is indicated. Almost the exact same thing happens with the imperfect.
When a ו conjunction is prefixed to an imperfect form, the result is usually a sequential-imperfect (also called a wayyiqtol). The effect is that (1) the aspect is flipped to be a perfect aspect, and (2) we understand that the message of the text is advanced a step forward. This construction is extremely common. The reason being that so much of the Hebrew Bible consists of narrative. And in narratives, one thing happens after another thing after another thing. This progression in the narrative is most often expressed by use of the sequential-imperfect.
The big difference between the sequential-perfect and the sequential-imperfect (besides them being opposites) is that the sequential-imperfect does in fact take on a slightly different form than a “normal” ו + imperfect. That difference in form is seen by an a-class vowel underneath the ו.