From Biblical Hebrew Grammar for Beginners:
The way Biblical Hebrew handles time perspectives has been one of the most widely examined and debated topics in Biblical Hebrew scholarship. While Mishnaic Hebrew and later phases of the language exhibit a fairly simple tense-based system with past, present, and future tense expressed by the verb, the system in Biblical Hebrew is more complex, as any verb form can be used in reference to any of the tenses.
•The conjugations represent a perspective on a situation or action. By and large, the prefix
conjugation represents an action that is viewed as incomplete (ongoing, yet to occur, repetitive,
habitual, etc.), and the suffix conjugation an action that is viewed as complete, that is, single
and whole. These perspectives, referred to as imperfective and perfective, respectively,
constitute what is known as the “aspect system” of Biblical Hebrew. They reflect the position
taken by the discourse on the onset, duration, and completion of a situation or action.