فَأَمَّا نَوَافِلُ اللَّيْلِ فَقَالَ أَبُو حَنِيفَةَ رَحِمَهُ اللَّهُ: إِنْ صَلَّى ثَمَانِيَ رَكَعَاتٍ بِتَسْلِيمَةٍ وَاحِدَةٍ جَازَ، وَيُكْرَهُ الزِّيَادَةُ عَلَى ذَلِكَ.
Translation: For nighttime voluntary prayer, Abu Hanifa said: up to eight rakahs with one salam is permissible; more than that is disliked.
This is a limit of permissibility; it does not imply that eight consecutive rakahs are always superior.
This ruling concerns joining multiple night rakahs in a single prayer and draws on reports describing longer voluntary night prayers.