Sayyiduna Hudhayfah (may Allah be pleased with him) said: Three types of people can give fatwa: the Imam, or the ruler of the government, or the person who is knowledgeable about the abrogating and abrogated verses of the Qur'an. The people asked: Who can such a person be? He said: Either Sayyiduna Umar ibn al-Khattab (may Allah be pleased with him), or a foolish ignoramus who takes it upon himself.
Hadith Referenceسنن دارمي / مقدمه / 177
Hadith Gradingتحقیق (حسین سلیم أسد الدارانی):إسناده ضعيف لانقطاعه محمد بن سيرين لم يدرك حذيفة، [مكتبه الشامله نمبر: 177]
Hadith Takhrijاس روایت کی سند ضعیف ہے، لیکن اثر کی نسبت صحیح ہے۔ دیکھئے: [الفقيه 1194] ، [جامع بيان العلم 2214، 2217]
Sayyiduna Hudhayfah (may Allah be pleased with him) said: One of three can give a fatwa. The one who has knowledge of the abrogating and abrogated. The people asked: Who is such a person? He replied: Sayyiduna Umar ibn al-Khattab (may Allah be pleased with him), or such a leader who has no choice but to give a fatwa, or a foolish person who takes it upon himself. Then Muhammad ibn Sirin (may Allah have mercy on him) said: I am not among those two (i.e., the ruler or governor), and I hope not to become the third (the foolish self-imposer) either.
Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said: Whoever among you has knowledge should make it apparent, and whoever does not have knowledge should say about what he does not know: «لا أعلم» (that is, "I do not know"), because if a scholar is asked about something he does not know, he should say «الله أعلم», just as Allah Almighty said to His Messenger (peace and blessings be upon him): "Say: I do not ask you for any reward for it, nor am I one of those who pretend." [سورة ص: 86/38]
Hadith Referenceسنن دارمي / مقدمه / 179
Hadith Gradingتحقیق (حسین سلیم أسد الدارانی):إسناده صحيح والحديث متفق عليه، [مكتبه الشامله نمبر: 179]
Hadith Takhrijاس روایت کی سند صحیح ہے۔ دیکھئے: [بخاري 4774] ، [مسند الحميدي 116] و [صحيح ابن حبان 4764]
It is narrated from Abu al-Muhallab that Sayyiduna Abu Musa Ash'ari (may Allah be pleased with him) said during a sermon: Whoever has knowledge should teach the people, and beware, whoever does not have knowledge about something should not say anything regarding it. If he does so, he will go out of the religion and will be among those who are pretentious.
Abu’l-Bakhtari and Zadhan said: Sayyiduna Ali (may Allah be pleased with him) said: How much coolness of the heart there is when I am asked about something of which I have no knowledge, and I say «الله أعلم» “Allah knows best.”
Hadith Referenceسنن دارمي / مقدمه / 181
Hadith Gradingتحقیق (حسین سلیم أسد الدارانی):إسناده ضعيف خالد بن عبد الله متأخر السماع من عطاء، [مكتبه الشامله نمبر: 181]
Hadith Takhrijاس روایت کی سند ضعیف ہے۔ دیکھئے: [جامع بيان العلم 1405]
Abu’l-Bakhtari narrated: Sayyiduna Ali (may Allah be pleased with him) said: How good it is (how soothing to the heart) that you say about what you do not know: «الله أعلم»
Hadith Takhrijاس قول کی سند بھی ضعیف ہے۔ ابوالبختری کا نام سعید بن فیروز ہے جن کا لقاء سیدنا علی رضی اللہ عنہ سے ثابت نہیں ہے۔ یہ روایت [الفقيه والمتفقه 71/2] میں کئی طرق سے موجود ہے، اور اس کے صحیح شواہد بھی موجود ہیں، معنی بھی صحیح ہے۔
It is narrated from Abu Nu’man Razin that Sayyiduna Ali bin Abi Talib, may Allah be pleased with him, said: When you are asked about something you do not know, then run away from answering it. Razin said: O Commander of the Faithful! How should we run away? He replied: Say «الله أعلم».
It is narrated from Uzrah Tamimi that Sayyiduna Ali (may Allah be pleased with him) said three times: "It is the coolness of the heart." The people asked: "What is that, O Commander of the Faithful?" He replied: "That a man is asked about something he does not know, and he says: «الله أعلم»"
Hisham bin Urwah narrated from his father (Urwah) that a man asked Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) about an issue, so he said: I do not know about it. When that man left, Sayyiduna Ibn Umar (may Allah be pleased with them both) said: What Ibn Umar said was correct; he was asked about something he did not know, so he said: I do not know about it.
Nafi' said: A man came and asked Sayyiduna Ibn Umar (may Allah be pleased with them both) about something, so he said: I do not know. Then when the man went away, he turned and said: What Ibn Umar said was correct. He is asked about something he does not know, so he said: I do not know (i.e., about himself).
It is narrated from Sayyiduna Mughira (may Allah be pleased with him) that when Sayyiduna Amir al-Sha'bi (may Allah be pleased with him) was asked about something, he would say «لا أدري» (I do not know). If he was asked again, he would say firmly: I swear by Allah for you, if I had knowledge of it (that is, by Allah, I do not have knowledge of it).
Hadith Referenceسنن دارمي / مقدمه / 188
Hadith Gradingتحقیق (حسین سلیم أسد الدارانی):إسناده ضعيف لضعف محمد بن حميد، [مكتبه الشامله نمبر: 188]
Hadith Takhrijاس روایت کی سند ضعیف ہے۔ خطیب نے [الفقيه والمتفقه 184/2] میں اس روایت کو ذکر کیا ہے، لیکن اس کی سند بھی ضعیف ہے۔
It is narrated from Ash'ath, may Allah have mercy on him, that Imam Muhammad bin Sirin, may Allah have mercy on him, said: I do not care whether I am asked about something I know or not. Because if I am asked about something I know, I answer accordingly, and if I do not know, I say «لا أعلم» that I do not know.
It is narrated from A‘mash that I never heard Imam Ibrahim al-Nakha‘i (may Allah have mercy on him) say that this is halal and this is haram; rather, he used to say: People considered this disliked, or people considered this recommended.