Absolute Infinitive and Infinitive Construct in Hebrew

In Brief

Formal Hebrew can compress a time clause into ב־ + infinitive construct + a pronoun ending: בבואי means “when I come/came,” and בצאתו means “when he leaves/left.” The same older infinitival system survives in fixed connectors such as לאמור (“that is to say”) and לרבות (“including”). These forms are commonest in writing, announcements, official language, and elevated style—not in relaxed everyday conversation.

Overview

Modern learners first meet the Hebrew infinitive as שם הפועל, usually a form beginning with ל־, such as לכתוב (“to write”) or להגיע (“to arrive”). The forms in this article belong to an older and more formal layer. They can act more like verbal nouns: they may follow a preposition and take an attached ending that identifies the subject. A verbal noun is simply a verb form used in some ways like a noun.

The central B1 pattern is a shortened time clause. Instead of writing כאשר הגעתי הביתה (“when I arrived home”), formal Hebrew can use בהגיעי הביתה (“upon my arrival home”). English has comparable phrases with “on/upon + -ing,” but the Hebrew ending matters: ־י in בהגיעי tells us that the person arriving is “I.” English speakers therefore need to resist treating the form as an unchanged infinitive.

There is an important terminology warning. In strict Hebrew grammar, the forms used after ב־, כ־, and sometimes ל־ are forms of the infinitive construct (מקור נטוי), while מקור מוחלט, the absolute infinitive, is a distinct, mainly Biblical form. Course materials sometimes place these older infinitival uses together or label the topic loosely. This article teaches the modern formal pattern named in the concept, then distinguishes the Biblical absolute infinitive in the advanced section.

How It Works

The core time-clause pattern

The most useful structure is:

ב־ + infinitive construct + subject ending + the rest of the phrase

It usually means “when …,” “as …,” or “upon …-ing.” The tense comes from the surrounding sentence, not from the infinitive itself:

• בהגיעי הביתה, אתקשר. — “When I arrive home, I’ll call.”
• בהגיעי הביתה, התקשרתי. — “When I arrived home, I called.”

The form בהגיעי does not independently say “present,” “past,” or “future.” The main verb—אתקשר or התקשרתי—and the context supply the time reference.

Attached endings identify the subject

An attached pronominal suffix (an ending that stands for a pronoun) tells the reader who performs the infinitive’s action. The exact stem varies with the verb, but the endings are broadly recognizable.

Person	Typical ending	Example with בוא “come”	Meaning
I	־י	בבואי	when I come/came
you, masculine singular	־ךָ	בבואךָ	when you come/came
you, feminine singular	־ךְ	בבואךְ	when you come/came
he	־וֹ	בבואו	when he comes/came
she	־הּ	בבואהּ	when she comes/came
we	־נוּ	בבואנו	when we come/came
you, plural	־כם / ־כן	בבואכם / בבואכן	when you all come/came
they	־ם / ־ן	בבואם / בבואן	when they come/came

Without vowel points, several endings can look similar, and feminine forms such as בבואה may be visually ambiguous. Context usually resolves the meaning. In ordinary formal writing, masculine plural ־ם often appears for mixed or unspecified groups, following general Hebrew agreement conventions.

The stem is not always the familiar ל־ infinitive

Do not simply remove ל־ from every dictionary infinitive and attach an ending. Some relationships are transparent, but others involve a traditional construct stem:

Familiar infinitive	Formal construct phrase	Meaning
לבוא	בבואו	when he comes/came
לצאת	בצאתו	when he leaves/left
להגיע	בהגיעי	when I arrive/arrived
להיכנס	בהיכנסם	when they enter/entered
להיוודע	בהיוודע הדבר	when the matter became known

It is safer to learn frequent forms as complete chunks—בבואי, בצאתו, בהגיעם—and then notice their endings. Productive formation depends on the verb’s binyan (its conjugation pattern) and is not equally natural with every verb.

Other prepositions

ב־ is the main preposition for “when/upon.” Formal language also uses:

• כ־ for “as/when,” often presenting two events as simultaneous: כראותו את השוטר (“when/as he saw the police officer”). This is elevated or literary.
• ל־ in older or fixed expressions. In modern texts, forms such as לאמור and לרבות function mainly as established connectors rather than freely built time clauses.

Do not confuse the ל־ in a fixed formal word with the ordinary infinitive marker in לכתוב. Their histories and present-day functions overlap, but learners use them differently.

Fixed formal connectors

Two especially useful items should be learned as vocabulary:

• לאמור — “that is to say,” “namely”; it introduces a reformulation or explanation.
• לרבות — “including”; it is common in legal, administrative, and policy language.

They normally have no attached subject ending. In everyday Hebrew, speakers are more likely to choose כלומר for “that is to say” and כולל for “including.”

Examples in Context

Hebrew	English	Note
בהגיעי הביתה, אתקשר.	When I arrive home, I’ll call.	־י marks “I”; future meaning comes from אתקשר.
בצאתו מהבית, התחיל לרוץ.	Upon leaving the house, he started to run.	־ו marks “he”; the main verb places the event in the past.
בבואכם למשרד, פנו לקבלה.	When you arrive at the office, go to reception.	־כם addresses more than one person.
בשובנו מן הטיול, גילינו שהדלת פתוחה.	When we returned from the trip, we discovered that the door was open.	־נו marks “we.”
בהיכנסה לאולם, הקהל מחא כפיים.	As she entered the hall, the audience applauded.	A formal feminine singular form.
בהיוודע התוצאות, נפרסם הודעה.	When the results become known, we will publish an announcement.	The following noun, התוצאות, supplies the subject.
עם סיום הישיבה נשלח את הסיכום.	When the meeting ends, we will send the summary.	A common modern alternative using עם + noun.
כאשר יצא מהבית, התחיל לרוץ.	When he left the house, he started to run.	Neutral alternative to בצאתו.
ההטבה חלה על כל העובדים, לרבות עובדים זמניים.	The benefit applies to all employees, including temporary employees.	Administrative use of לרבות.
נדרש אישור מזהה, לאמור תעודת זהות או דרכון.	An identifying document is required, namely an identity card or passport.	לאמור introduces clarification; the style is formal.
כראותו את האור, עצר לרגע.	When he saw the light, he stopped for a moment.	Elevated or literary כ־ construction.
בבוא העת נדון בפרטים.	When the time comes, we will discuss the details.	בבוא העת is a common fixed phrase.

Notice that formal infinitive clauses often come before the main clause and are followed by a comma. They can also appear later, but front position makes the time relationship especially clear.

Common Mistakes

Attaching the ending to the ordinary ל־ infinitive

• Wrong: בלבואו הביתה, התקשר.
• Right: בבואו הביתה, התקשר.
• Why: This construction uses the infinitive-construct stem בוא, not the everyday infinitive לבוא with another preposition added in front.

Omitting the subject information

• Wrong: בהגיע הביתה, התקשרתי.
• Right: בהגיעי הביתה, התקשרתי.
• Why: If “I” am the person arriving, ־י makes that explicit. A suffixless form can be possible when a following noun is the subject, as in בהגיע הרכבת (“when the train arrives”), but it cannot silently stand for any personal subject.

Making the implied subject disagree with the main clause

• Wrong: בצאתו מהבית, התחלתי לרוץ. if the intended meaning is “When I left, I started running.”
• Right: בצאתי מהבית, התחלתי לרוץ.
• Why: ־ו means “his/he,” while ־י means “my/I.” The implied subject must match the intended doer.

Treating the form as a past tense

• Wrong idea: בהגיעי always means “when I arrived.”
• Right: בהגיעי can mean “when I arrive” or “when I arrived.”
• Why: The main clause and context determine time. Compare אתקשר (“I’ll call”) with התקשרתי (“I called”).

Using formal forms in casual conversation without a reason

• Awkward in ordinary chat: בבואי הביתה, אשלח לך הודעה.
• More natural in conversation: כשאגיע הביתה, אשלח לך הודעה.
• Why: The first is grammatical but sounds written or elevated. Everyday speech normally uses כש־ plus a finite verb—a verb marked for person and tense.

Using לרבות when כולל is the natural choice

• Overly official: הבאתי פירות, לרבות תפוחים ובננות.
• Natural conversation: הבאתי פירות, כולל תפוחים ובננות.
• Why: לרבות is strongly associated with formal, administrative, and legal prose.

Usage Notes

These constructions are primarily part of register, meaning the style chosen for a situation. You will encounter them in contracts, regulations, public notices, formal correspondence, journalism, ceremonial language, and literary prose. Some phrases, especially בבוא העת (“when the time comes”), are familiar enough to appear outside highly official writing.

In neutral modern Hebrew, a full clause is usually easier and more natural:

• בצאתו מהבית → כשהוא יצא מהבית
• בהגיעי למשרד → כשאגיע למשרד or כשהגעתי למשרד, depending on time
• בהיוודע התוצאות → כשהתוצאות ייוודעו

English “upon arriving” can encourage a misleading word-for-word approach. English leaves the subject to context in many such phrases; Hebrew formal style often marks it directly with a suffix. Conversely, English demands a tense choice in “when I arrive” versus “when I arrived,” whereas the Hebrew infinitive form itself remains tenseless.

Use the compressed construction when brevity, solemnity, or an impersonal official tone is wanted. Use כש־/כאשר plus a regular verb when clarity and natural conversation matter more.

Beyond the Basics: The True Absolute Infinitive

In strict terminology, the Biblical Hebrew absolute infinitive (מקור מוחלט) is not the suffixed time-clause form described above. It is an uninflected form—one that does not change for person—often placed next to a finite verb from the same root for emphasis, certainty, or intensity. A well-known pattern is:

absolute infinitive + finite verb

For example, Biblical שָׁמוֹר תִּשְׁמְרוּן has the force of “you shall surely keep.” Biblical texts also contain מוֹת תָּמוּת, traditionally rendered “you shall surely die.” The first word reinforces the second; it is not a subject-marked time clause.

This construction is not productive everyday Modern Hebrew grammar. It matters mainly for reading the Bible, older literature, quotations, and deliberate Biblical-style rhetoric. Modern Hebrew normally expresses emphasis with adverbs, repetition, intonation, or other ordinary syntax.

The terminology can therefore be summarized as follows:

Technical category	Typical example	Main function today
Infinitive construct with preposition/suffix	בבואי, בצאתו	Formal compressed clause
Fixed infinitival connector	לאמור, לרבות	Formal linking word
Absolute infinitive in the strict sense	שמור תשמרון	Biblical emphasis; recognition rather than everyday production

For production, prioritize the first two rows. For advanced reading, learn to recognize the third and avoid assuming that every item called מקור מוחלט behaves like בבואי.

Practice Tips

1. Build three-way pairs. Rewrite בצאתו מהבית as כשהוא יצא מהבית and then translate both as “when he left the house.” This trains meaning and register together.
2. Highlight the ending. In every form you meet, underline ־י, ־ו, ־נו, ־ם and name the subject before translating. Then identify the main verb that supplies the time frame.
3. Collect real examples by source. Keep separate lists from news or official notices and from conversation. This prevents a useful reading form from becoming an unnatural speaking habit.

Related Concepts

• Prerequisite: Infinitive Forms — review ordinary ל־ infinitives and Hebrew verb patterns before studying formal construct stems.