يجب أن

Must

Level 2

Use يجب أن (yajibu an) to express mandatory obligation. The verb يجب stays in the 3rd person masculine singular form, while the following verb changes to match the subject.

How It Works

The expression يجب أن is the standard way to convey obligation in formal Arabic.

1. The Verb Form:
The verb يجب (from the root w-j-b) is typically used in the 3rd person masculine singular form when followed by أن and a verb. However, if followed directly by a feminine verbal noun, it can conjugate for gender, such as تجبُ المذاكرةُ (Studying is necessary).

2. Specifying the Agent:
Unlike English, you do not need a preposition to identify who must do the action; the subject is usually identified by the conjugation of the verb following أن. For example, يجب أن أذهبَ (I must go). To add emphasis or denote a specific duty, you can use the preposition على followed by a noun or a pronoun suffix, as in يجب عليك أن تدرسَ (It is incumbent upon you to study).

3. The Subjunctive Clause:
After يجب أن, you must use a verb in the subjunctive mood. This usually means the verb ends in a fatḥa (-a) for singular subjects, or follows the rule for dropping the ن for plural subjects.

4. Past Obligation:
To say someone "had to" or "should have" done something, use the verb كان before the expression: كان يجب أن. For example, كان يجب أن نسافرَ أمس (We had to travel yesterday).

5. Using the Verbal Noun:
Alternatively, you can follow يجب directly with a verbal noun (maṣdar). In this case, the particle أن is removed. The verbal noun acts as the subject (fā‘il) and must be in the nominative case (ending in a damma). For example, يجبُ الذهابُ (Going is necessary / One must go).

6. Nuance and Prepositions:
This pattern is stronger than يمكن أن (it is possible). While يجب (must) takes the preposition على for the person obligated, the related verb ينبغي (should/ought to) traditionally takes the preposition لِـ to denote desirability for the person involved.

7. Negation:
There is a critical difference in negation: لا يجب أن means 'it is not necessary' (you don't have to), whereas يجب ألا (a contraction of أن + لا) means 'it is necessary not to' (you must not/prohibition). In both cases, the verb following أن or ألا remains in the subjunctive.

Examples (5)

  1. يجب أن تدرسَ جيداً للنجاح.

    You must study well to succeed.

    Word by Word: It is necessary that you study well for the success.

    Notice that 'yajibu' is masculine singular, while 'tadrusa' is conjugated for 'you' in the subjunctive.

  2. يجب أن نحميَ البيئةَ.

    We must protect the environment.

    Word by Word: It is necessary that we protect the environment.

    The verb 'naḥmiya' (we protect) takes the subjunctive ending because of 'an'.

  3. يجب على الطلاب أن يكتبوا الواجب.

    The students must write the homework.

    Word by Word: It is necessary upon the students that they write the homework.

    Adding 'على' (upon) specifies who the obligation is directed toward, though the verb 'yajibu' remains unchanged.

  4. يجبُ الحذرُ في هذا المكان.

    Caution is necessary in this place.

    Word by Word: Is necessary the caution in this place.

    This example uses the verbal noun (al-ḥadhar) in the nominative case as the subject of 'yajibu'.

  5. يجب ألا ننسى هذا الأمر.

    We must not forget this matter.

    Word by Word: It is necessary that not we forget this matter.

    The contraction 'ألا' (an + lā) is used for prohibition (must not), and the following verb remains in the subjunctive.

Common Mistakes

  • Conjugating the verb 'يجب' to match the person.

    أجب أن أذهب إلى العمل.
    يجب أن أذهب إلى العمل.

    Learners often try to say 'I must' by changing 'yajibu' to 'ajibu'. In MSA, 'yajibu' stays in the 3rd person masculine singular form regardless of the subject.

  • Using the indicative mood (ending in -u) instead of the subjunctive (ending in -a) after 'أن'.

    يجب أن تذهبُ.
    يجب أن تذهبَ.

    The particle 'an' always triggers the subjunctive mood in the following verb.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

يجب أنLevel 2Must

Learn This First

To use 'يجب أن' (must), you need to understand how to conjugate verbs in the present tense and how the particle 'أن' functions to link two verbs together while putting the second verb into the subjunctive mood.

Words in This Pattern

وجبأن