Al-Kāfi

Hadith 691
death
1ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ رَفَعَهُ قَالَ قُلْتُ لأَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) لِمَ جُعِلَ التَّكْبِيرُ عَلَى الْمَيِّتِ خَمْساً فَقَالَ وَرَدَ مِنْ كُلِّ صَلاَةٍ تَكْبِيرَةٌ.
1. Ali ibn Ibrahim has narrated from his father from in a mafu’ manner the following: “I asked abu ’Abd Allah (a.s.), ’Why are there five Takbir in Salah (prayer) for a dead person?’ He (the Imam) replied, ’From every Salah (prayer) of a day’s Salah (prayer), one Takbir has come.’”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī