Al-Kāfi

Hadith 1146
call-to-prayer
26ـ جَمَاعَةٌ مِنْ أَصْحَابِنَا عَنْ أَحْمَدَ بْنِ مُحَمَّدِ بْنِ عِيسَى عَنْ مُحَمَّدِ بْنِ سِنَانٍ عَنِ الْحَسَنِ بْنِ السَّرِيِّ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) قَالَ الأذَانُ تَرْتِيلٌ وَالإِقَامَةُ حَدْرٌ.
26. A group of our people has narrated from Ahmad ibn Muhammad ibn ‘Isa from Muhammad ibn Sinan from al-Hassan ibn al-Sariy who has said the following: “Abu ‘Abd Allah (a.s.), has said, ‘Adhan is said with Tartil (articulation slowly) and ‘Iqamah is said quickly.’”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī