فَإِنْ مِتُّ فَانْعِينِي بِمَا أَنَا أَهْلُهُ
وَشُقِّي عَلَيَّ الْجَيْبَ يَا ابْنَةَ مَعْبَدِ
Meaning: If I die, announce my death in a manner befitting my qualities, and, daughter of Maʿbad, tear your garment at the neck in mourning for me.
Fa-in mittu introduces a condition, fa-nʿaynī is a feminine singular command to announce a death, and shuqqī al-jayb depicts tearing the neckline of a garment in mourning. The addressee is the daughter of Maʿbad. This depicts a pre-Islamic mourning practice; it is not a religious instruction.