Jabir bin Samura reported,
The people of Kufa complained about Saad to Umar 
, so he removed him from his post and appointed Ammar over them. They complained again, even claiming that he did not know how to pray properly. So Umar sent for him and said, "Abu Ishaq, these people claim that you do not know how to pray well."Abu Ishaq replied, "By Allah, I used to lead them in prayer just as the Messenger of Allah ﷺ prayed, without falling short of it in any way. I would pray the evening prayer, prolonging the first two units and shortening the last two."Umar said, "That is what I expected of you, Abu Ishaq."Then Umar sent a man, or some men, with him to Kufa to inquire about him. The envoy asked the people of Kufa about him, leaving no mosque without making inquiries, and they all spoke well of him. Finally, he entered a mosque belonging to Banu Abs, where a man among them named Usama bin Qatada, known as Abu Sadah, stood up and said, "Since you have asked us under oath, Saad did not march with the army, did not distribute the spoils equitably, and did not judge fairly."Saad said, "By Allah, I shall make three supplications. O Allah, if this servant of Yours is lying and stood up out of showing off and seeking reputation, then prolong his life, prolong his poverty, and expose him to trials."After that, whenever the man was asked about himself, he would say, "I am an old man tried by tribulations. The supplication of Saad has struck me."Abdul-Malik said, "I saw him afterwards. His eyebrows had drooped down over his eyes from old age, and he was harassing young girls in the streets, pinching them."
Azami 9964
Sahihعن جابر بن سمرة قال
شكا أهل الكوفة سعدا إلى عمررضي الله عنه فعزله واستعمل عليهم عمارا، فشكوا حتى ذكروا أنه لا يحسن يصلي، فأرسل إليه فقال: يا أبا إسحق إن هؤلاء يزعمون أنك لا تحسن تصلي؟ قال أبو إسحق: أما أنا والله فإني كنت أصلي بهم صلاة رسول الله ﷺ ما أخرم عنها، أصلي صلاة العشاء فأركد في الاولين، وأخف في الأخريين. قال: ذاك الظن بك يا أبا إسحق. فأرسل معه رجلا أو رجالا إلى الكوفة، فسأل عنه أهل الكوفة، ولم يدع مسجدا إلا سأل عنه، ويثنون معروفا حتى دخل مسجدا لبني عبس، فقام رجل منهم، يقال له: أسامة بن قتادة، يكنى أبا سعدة، قال: أما إذ نشدتنا، فإن سعدا كان لا يسير بالسرية، ولا يقسم بالسوية، ولا يعدل في القضية. قال سعد: أما والله لأدعون بثلاث: اللهم إن كان عبدك هذا كاذبا قام رياء وسمعة فأطل عمره، وأطل فقره، وعرضه بالفتن. وكان بعد إذا سئل يقول: شيخ كبير مفتون أصابتني دعوة سعد. قال عبد الملك: فأنا رأيته بعد قد سقط حاجباه على عينيه من الكبر، وإنه ليتعرض للجواري في الطرق يغمزهن.
Bukhari narrated it in adhan (755) from Musa, who said, Abu Awana narrated to us, who said, Abdul-Malik bin Umayr narrated to us, from Jabir bin Samura, who said, and then he related it. This is his wording.Muslim narrated it in prayer (453) through another route from Abdul-Malik bin Umayr, and he related it restricting himself to the matter of prayer only.It was narrated from Saad bin Abu Waqqas that the Messenger of Allah ﷺ said, "O Allah, answer Saad's prayer when he calls upon You."Tirmidhi narrated it (3751), Ibn Abu Asim in Sunnah (1444), and Bazzar in Kashf Astar (2579), Ibn Hibban graded it sahih (6990), and Hakim (499/3), all of them through the route of Jafar bin Awn, who said, Ismail bin Abu Khalid narrated to us, from Qays bin Abu Hazim, from Saad, and he related it.Bazzar said, "Jafar bin Awn is the only one who narrated it with this isnad."I say, Musa bin Uqba corroborated him, from Ismail bin Abu Khalid, from Qays bin Abu Hazim, from Saad bin Abu Waqqas, who said, The Messenger of Allah ﷺ said to me, "O Allah, make his shots accurate, and answer his prayer."Abu Naeem narrated it in Hilya (93/1), and Hakim (3/500), both of them through the route of Ibrahim bin Shajari, from his father (who is Yahya bin Muhammad bin Abbad), who said, Musa bin Uqba narrated it to me in this form. Ibrahim bin Yahya Shajari and his father are both daif. There is disagreement regarding Ibrahim, for at one time he narrated it this way, and at another time he narrated it without mentioning Musa bin Uqba, as found in Sharh al-Sunnah (3922).Tirmidhi said, "This hadith has also been narrated from Ismail, from Qays, that the Prophet ﷺ said, 'O Allah, answer Saad's prayer when he calls upon You,' and this is more correct."The mursal report that Tirmidhi pointed to was narrated by Ibn Saad in Tabaqat (142/3) from Yazid bin Harun, and by Ahmad in Fadail al-Sahabah (1308) from Yahya (who is Qattan), both of them from Ismail bin Khalid, from Qays bin Abu Hazim, who said, I was informed that the Messenger of Allah ﷺ said to Saad, and then he related it.Daraqutni was asked about this hadith, and he said, "Jafar bin Awn and Jafar bin Amr bin Hurayth connected the chain fully, from Ismail bin Abu Khalid, from Qays, from Saad. Zaida, Sufyan bin Uyayna, Hushaym, Abu Usama, and Hakam disagreed with him, and they narrated it from Ismail, from Qays, as a mursal report from the Prophet ﷺ, and this is the preserved version."