Al-Kāfi - Volume 1 > The Angels come to the Houses of the Imams, Step on their Furnishings and Bring them News
Hadith #4

4ـ مُحَمَّدٌ عَنْ مُحَمَّدِ بْنِ الْحَسَنِ عَنْ مُحَمَّدِ بْنِ أَسْلَمَ عَنْ عَلِيِّ بْنِ أَبِي حَمْزَةَ عَنْ أَبِي الْحَسَنِ (عَلَيْهِ السَّلام) قَالَ سَمِعْتُهُ يَقُولُ مَا مِنْ مَلَكٍ يُهْبِطُهُ الله فِي أَمْرٍ مَا يُهْبِطُهُ إِلا بَدَأَ بِالامَامِ فَعَرَضَ ذَلِكَ عَلَيْهِ وَإِنَّ مُخْتَلَفَ الْمَلائِكَةِ مِنْ عِنْدِ الله تَبَارَكَ وَتَعَالَى إِلَى صَاحِبِ هَذَا الامْرِ.

4. Muhammad has narrated from Muhammad ibn al-Hassan from Muhammad ibn Aslam from Ali ibn abu Hamza who has said the following. “I heard abu al-Hassan (a.s.) say, ‘Every angels that Allah sends down for a task that angel first begins with meeting the Imam to present the task to him. The presence of Imam, Leader with Divine Authority is the scene of great mix of the angels from Allah, the Most Holy, the Most High.”