Hadithcore
Mishkat al-Masabih, 2362

He reported God’s messenger as saying, “If anyone meets God, not having treated anything as equal to Him in the world, and has committed sins equal in quantity to the mountains, God will forgive him.” Baihaqi transmitted it in <i>Kitab al-ba'th wan-nushur</i>.

وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مَنْ لَقِيَ اللَّهَ لَا يَعْدِلُ بِهِ شَيْئًا فِي الدُّنْيَا ثُمَّ كَانَ عَلَيْهِ مِثْلَ جِبَالٍ ذُنُوبٌ غَفَرَ اللَّهُ لَهُ» . رَوَاهُ الْبَيْهَقِيّ فِي كتاب الْبَعْث والنشور

References1 variant
In-Book Reference
Book 9, Hadith 135