The judge's independent reasoning

Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: Two disputants brought their case before Sayyiduna Amr bin al-As (may Allah be pleased with him), and he judged between them. The one against whom the judgment went was displeased, so he went to the Prophet (peace and blessings be upon him) and told him about it. He said: "When the judge, in giving judgment, exercises his independent reasoning (ijtihad) and judges correctly, he receives a tenfold reward; and when he exercises his reasoning and errs, he receives one (the narrator is unsure; perhaps the words are: or) two rewards."
Ahmad recorded it, and al-Tabarani in al-Mu'jam al-Awsat; its chain contains Salamah bin Uksum, and I have not found anyone who has given an account of him.

Sayyiduna Amr bin al-As (may Allah be pleased with him) narrates: Two men came to the Prophet (peace and blessings be upon him), opposing parties in a dispute. The Prophet (peace and blessings be upon him) said to Sayyiduna Amr (may Allah be pleased with him): "O Amr, judge between the two of them." He said: "O Messenger of Allah, you are more entitled to this than I am." The Prophet (peace and blessings be upon him) said: "Even if that is so (you judge)." He said: "If I judge between them, what will I get?" The Prophet (peace and blessings be upon him) said: "If you judge between them and judge correctly, you will get ten good deeds; and if you exercise your reasoning (ijtihad) and err, you will get one good deed." (Allamah al-Haythami says:) I say: From him, in the "Sahih",
this report is narrated: "If you judge correctly, you will receive a double reward, and if you err, you will receive one reward."
Ahmad recorded it, and al-Tabarani in al-Mu'jam al-Kabir; its chain contains a narrator whom I do not know.

Ahmad recorded, with his chain whose narrators are the narrators of the Sahih, from Sayyiduna Uqbah bin Amir (may Allah be pleased with him), from the Prophet (peace and blessings be upon him), a report similar to this, except that its wording is: "If you exercise your reasoning (ijtihad) and judge correctly, you will get ten rewards; and if you exercise your reasoning and err, you will get one reward."

Sayyiduna Uqbah bin Amir al-Juhani (may Allah be pleased with him) narrates: I came to the Prophet (peace and blessings be upon him), and at that time two opposing parties were present before him who had brought a case. The Prophet (peace and blessings be upon him) said to me: "Judge between the two of them." I said: "May my father and mother be sacrificed for you, you are more entitled to this than I am." The Prophet (peace and blessings be upon him) said: "Judge between them." I said: "On what basis?" The Prophet (peace and blessings be upon him) said: "Exercise your reasoning (ijtihad). If you judge correctly, you will get ten good deeds, and if you do not judge correctly, you will get one good deed."
Al-Tabarani recorded it in al-Mu'jam al-Saghir and al-Mu'jam al-Awsat; its chain contains Hafs bin Sulayman al-Asadi, who is matruk (abandoned). It has already been mentioned before this that Ahmad recorded it with a chain whose narrators are the narrators of the Sahih.

Sayyiduna Buraydah (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Judges are of three kinds: a man who, in giving judgment, exercises his reasoning (ijtihad) and judges correctly, he will attain Paradise; a man who, in giving judgment, exercises his reasoning and errs, he too will attain Paradise; and a man who judges with injustice, he will go to Hell." (Allamah al-Haythami says:) I say: Abu Dawud recorded from a Companion this report: "Judges are of three kinds: one kind of judge will go to Paradise and two kinds of judges will go to Hell."
Al-Tabarani recorded it in al-Mu'jam al-Awsat, and its narrators are the narrators of the Sahih.