Western languages encode when something happens — past, present, future. Hebrew encodes whether it is complete or incomplete. This is called verbal aspect.

Perfect (Qatal) — the action is viewed as complete, whole, a single event. This is usually past, but not always.
Imperfect (Yiqtol) — the action is incomplete, ongoing, repeated, or habitual. Usually future or present, but not always.

The Prophet Isaiah writes about future events in the Perfect tense — the "prophetic perfect" — because to him the event is already complete in God's perspective. Hebrew embeds theology in its grammar.

The Perfect conjugation takes suffixes — endings added after the root. The root used here is שמר (shamar — to guard). Suffixes encode person, gender, and number.

The Imperfect takes prefixes — and sometimes both prefixes and suffixes. The prefix encodes person and sometimes gender; the suffix (when present) adds number. The prefix pattern is אֶ / תִ / יִ / נִ.

This is the most important feature of Biblical Hebrew narrative. The prefix וַ (vav with dagesh) attached to the Imperfect creates a past narrative form. The prefix וְ (vav simple) + Perfect creates a future sequence.

Vav HaHippuch (וְהָפַךְ הַכֹּל) — "the Vav that reverses everything." It flips the aspect. This is why almost all narrative in the Torah is written in the Imperfect — because the chain of wayiqtol forms carries the story forward.

The participle (בֹּנֶה — boné, building) expresses an ongoing, durative state. It does not encode time at all — context determines when. It functions both as a verb and as a noun or adjective.