وَعَن أبي سعيد [الْخُدْرِيّ] عَنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «الصَّعُودُ جَبَلٌ مِنْ نَارٍ يُتَصَعَّدُ فِيهِ سَبْعِينَ خَرِيفًا وَيُهْوَى بِهِ كَذَلِكَ فِيهِ أَبَدًا» . رَوَاهُ التِّرْمِذِي
Translation

Abu Sa`id reported God's messenger as saying, "The ascent[*] is a mountain in hell up which people will be made to climb for seventy years and down which they will be made to fall a like distance, and so on forever." *Quran; 74:17.Tirmidhi transmitted it.