Site for researching all meanings of Hebrew Bible.
Grammar:Tutorial/Meaning of perfect and imperfect
A quote from this Web page:
There is no such thing as "tense" in biblical Hebrew. (Modern Hebrew, on the other hand, does have tenses.) Biblical Hebrew is not a "tense" language. Modern grammarians recognize that it is an "aspectual" language. This means that the same form of a verb can be translated as either past, present, or future depending on the context and various grammatical cues. The most well known grammatical cue is the "vav-consecutive" that makes an imperfective verb to refer to the past.
I recommend you to read some articles about Hebrew tenses such as this article.
There are also forms commonly called “reverse perfect” and “reverse imperfect” which are (in absence of vowels) just perfect and imperfect with a prefix ו (so called vav of reversal).
Vav of reversal is called so because the meaning of reverse perfect is similar to imperfect and the meaning of reverse imperfect is similar to perfect.
Modern science position is that similarity of reverse imperfect with imperfect is a coincidence from the position of history of the language. But this may be not a coincidence from theological positions.