لِّسَعْيِهَا

لِّسَعْيِهَا is a phrase (شِبْهُ الجُمْلَةِ) consisting of a genitive particle and a possessive nominal compound

PhraseParticle / Noun / NounNounNoun Particle
شِبْهُ الجُمْلَةِجَارٌ وَمَجْرُوْرٌ وَهُوَ مُضَافٌ وَ مُضَافٌ إِلَيْهِمُضَافٌ إِلَيْهِاسْمٌ مَجْرُوْرٌ وَهُوَ مَضَافٌحَرْفُ جَرٍّ
PhraseCompoundPossessive NounGenitive noun + Noun possessedParticle of pulling down
  
with their endeavourلِّسَعْيِهَا=هَا+سَعْيِ+لِّ
with the effort of theirstheirsthe effort ofwith
Surah/Below is the only verse in the holy Quran containing the phraseلِّسَعْيِهَا
Verse
89-9glad with their endeavorلِّسَعْيِهَا رَاضِيَةٌ