Idan muka yi abin da doka ta ce da haƙuri, ɗan sanda ba zai tsayar da mu ba.

Idan most often means if or when and is used to introduce a condition or a time clause.

In this sentence, Idan introduces the condition:

• Idan muka yi… = If / When we do…

Context decides whether you translate it as if (conditional) or when/whenever (general habit). Here, both are possible in English:

• If we do what the law says…
• When(ever) we do what the law says…

Hausa has different forms of the subject pronouns depending on the structure of the clause.

• mun yi = we did / we have done (normal perfective)
• muka yi = we did / we do in a relative/focus/subordinate environment, like after Idan, lokacin da, wanda, etc.

Here, Idan creates a special kind of clause (a conditional / subordinate clause), so Hausa uses the relative perfective form muka instead of mun:

• Idan muka yi… (correct)
• ✗ Idan mun yi… (sounds wrong or at least very unusual)

Even though the Hausa form is perfective, English naturally uses a present tense in if-clauses:

• Idan muka yi… → If we do… (not if we did in this kind of general statement)

Abin da is literally the thing that, and it’s a very common way to express what (as a relative pronoun) in Hausa.

• abu = thing
• abin = the thing (with the definite -n)
• da = that / which (here, a relative marker)

So:

• abin da doka ta ce = the thing that the law says = what the law says

In everyday writing and speech you will also see:

• abinda (everything merged)
• abin da (separated; more clearly shows the components)

They mean the same thing in this kind of structure.

Breakdown:

• abin da = what / the thing that
• doka = law
• ta ce = it (feminine) said / says

So the structure is:

• [abin da] [doka] [ta ce]
• what
  • law
    • it (fem.) says

The subject of ta ce is doka:

• doka ta ce = the law says

The whole phrase:

• abin da doka ta ce = what the law says

In Hausa, nouns have grammatical gender (masculine or feminine), and verbs agree with that gender through the subject pronoun:

• ya ce = he said / it (masc.) said
• ta ce = she said / it (fem.) said

The noun doka (law) is grammatically feminine, so you must use ta:

• doka ta ce = the law says

Using ya ce here would be grammatically wrong:

• ✗ doka ya ce (incorrect)

Literally:

• da = with
• haƙuri = patience; endurance; tolerance

So da haƙuri = with patience.

Hausa often forms an adverb-like meaning with da + noun:

• da sauri = with speed → quickly
• da hankali = with care → carefully
• da haƙuri = with patience → patiently

So here:

• Idan muka yi … da haƙuri = If we do … with patience / patiently

Yes, it’s the same basic da, which has several related uses:

1. And:

   • Ali da Musa = Ali and Musa

2. With (comitative / instrument / manner):

   • Ina tafiya da kai. = I’m going with you.
   • da haƙuri = with patience → patiently

3. As a “have” verb when used with ina:

   • Ina da kuɗi. = I have money. (literally: I am with money.)

In da haƙuri, it is the with / manner use.

Literally:

• ɗa / ɗan = son / child (masculine, often used as “guy/man of …”)
• sanda = stick, baton, rod

So ɗan sanda is something like “man of the stick”, i.e. the man with a baton → policeman.

Plural:

• ɗan sanda (sg.) = policeman
• 'yan sanda (pl.) = policemen / the police

Notice:

• The ɗ often drops in the plural spelling: ɗan → 'yan.

Standard Hausa sentence negation usually uses ba … ba (a pair):

1. First ba comes before the verb phrase.
2. Second ba closes the clause.

In the future tense:

• zai tsayar da mu = he will stop us
• ba zai tsayar da mu ba = he will not stop us

So in the full sentence:

• ɗan sanda = the policeman
• ba zai tsayar da mu ba = will not stop us

Together:

• ɗan sanda ba zai tsayar da mu ba. = The policeman will not stop us.

Dropping the second ba is non‑standard and sounds incomplete in careful speech.

Historically, zai comes from za ya:

• za (future marker) + ya (he / it masc.) → za ya → zai

In modern standard Hausa, the future with 3rd person masculine is usually written as a single word:

• zai tsayar da mu = he will stop us

Similarly:

• za ta → often written zata (she/it fem. will)
• za su → often written zasu (they will), though some prefer to keep them separate.

So zai here is the he/it will form of the future verb phrase.

• tsaya = to stand / to stop (oneself) (intransitive)

  • Motar ta tsaya. = The car stopped / stood still.

• tsayar da = to make (someone/something) stop; to stop (someone) (causative / transitive)

  • Ɗan sanda ya tsayar da mu. = The policeman stopped us (made us stop).

So:

• tsaya = stop/stand yourself.
• tsayar da = cause someone/something else to stop.

In the sentence:

• zai tsayar da mu = he will stop us (cause us to stop).

Both are 1st person plural (we/us), but they have different grammatical roles:

1. muka (in muka yi) = we as the subject in a relative/conditional clause.

   • muka = mu (we) + relative perfective marker.

2. mu (in tsayar da mu) = us as the object of the verb.

   • tsayar da mu = stop us

So:

• Idan muka yi … = If we do …
• ba zai tsayar da mu ba = he will not stop us

Yes. You can change wording while keeping the meaning that if we obey the law patiently, the police won’t stop us. For example:

• Idan muka bi doka da haƙuri, ɗan sanda ba zai tsayar da mu ba.
  • bi doka = follow/obey the law

Or, to make it sound even more natural:

• Idan muka bi dokar da haƙuri, 'yan sanda ba za su tsayar da mu ba.
  • dokar = the law (with the definite genitive ending)
  • 'yan sanda = policemen / the police (plural)
  • ba za su tsayar da mu ba = they will not stop us

All of these express essentially the same idea, with minor stylistic differences.