lanā
we had
P – prefixed preposition lām + PRON – 1st person plural personal pronoun nā
Root Link: ل
fanakūna
then we could be
CAUS – prefixed particle of cause fa + V – 1st person plural imperfect verb, subjunctive mood
Root Link: ك و ن
l-mu'minīna
the believers
DET – determiner prefix al + N – genitive masculine plural (form IV) active participle
Root Link: ا م ن