لَم يَنْتَهِ

لَم يَنْتَهِ is a verbal sentence (الجُمْلَةُ الفِعْلِيَّةُ) consisting of a jussive, past tense negative particle and a jussive, present tense verb

The natural state of the present tense verb is يَنْتَهِي however due to the presence of the jussive particle لَم that precedes it, it’s  state changes to لَم يَنْتَهِ

SentenceParticle / VerbVerb Particle
الجُمْلَةُ الفِعْلِيَّةُحَرْفٌ جَزْمٌ وَفِعْلٌ مَجْزُوْمٌفِعْلٌ مُضَارِعٌ مَجْزُوْمٌ بِالسُّكُوْنِ الزَّاهِرَةِحَرْفٌ جَزْمٌ
verbal sentenceSentencea present or future tense jussive verba jussive, past tense, negative particle
  
did not He restrainلَمْ يَنْتَهِ=يَنْتَهِ+لَم
did he not desistrestraindid not
Surah/Below are the 2 verses in the holy Quran containing the jussive particle and jussive verbلَم يَنْتَهِ
Verse
33-60
96-15Nay! if he ceases not, We will surely catch him by the forelockكَلَّا لَئِنْ لَّمْ يَنْتَهِ لَنَسْفَعًا بِالنَّاصِيَةِ