Al-Kāfi
Hadith 5663- أَحْمَدُ بْنُ مُحَمَّدٍ عَنْ مُحَمَّدِ بْنِ حَسَّانَ عَنْ إِدْرِيسَ بْنِ الْحَسَنِ عَنْ عَلِيِّ بْنِ غِيَاثٍ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ لا تَشْهَدَنَّ بِشَهَادَةٍ حَتَّى تَعْرِفَهَا كَمَا تَعْرِفُ كَفَّكَ.
3. Ahmad ibn Muhammad has narrated from Muhammad ibn Hassan from Idris ibn al-Hassan from Ali ibn Ghiyath who has narrated the following: “Abu ‘Abd Allah (a.s.), has said, ‘Do not testify for a case unless you know it as you know your palm.’”