The answering of Sa'd's (may Allah be pleased with him) supplication against a man who reviled Ali (may Allah be pleased with him) while riding a mount

Mus'ab bin Sa'd narrates from his father, Sayyiduna Sa'd (may Allah be pleased with him), that a man spoke insultingly of Sayyiduna Ali (may Allah be pleased with him), so Sayyiduna Sa'd bin Malik (may Allah be pleased with him) supplicated against him. Suddenly a she-camel or a camel came and killed him (by trampling him). After this incident, Sayyiduna Sa'd (may Allah be pleased with him) freed a soul (a slave) and swore that he would never again supplicate against anyone.

It is narrated from Qays bin Abi Hazim that he said: I was in Madinah, going around the market, when I reached the place called "Ahjar al-Zayt", and I saw a crowd of people gathered around a horseman who was reviling Sayyiduna Ali bin Abi Talib (may Allah be pleased with him), while the people stood around him listening. Just then Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) arrived, stood by them and asked: "What is going on?" The people said: "This man is reviling Ali bin Abi Talib." So Sayyiduna Sa'd (may Allah be pleased with him) went forward, and the people made way for him until he stood in front of that man, and he said: "O you! On what basis do you revile Ali bin Abi Talib? Was he not the first to accept Islam? Was he not the first person to pray with the Messenger of Allah (peace and blessings be upon him)? Was he not the most abstinent of people? Was he not the most knowledgeable of people?" He went on mentioning the virtues of Sayyiduna Ali (may Allah be pleased with him) until he said: "Was he not the son-in-law of the Messenger of Allah (peace and blessings be upon him), the husband of his daughter? Was he not the standard-bearer of the Messenger of Allah (peace and blessings be upon him) in the battles?" Then Sayyiduna Sa'd (may Allah be pleased with him) turned towards the Qiblah, raised his hands and supplicated: "O Allah, this man is reviling one of Your friends (awliya'), so show these people a sign of Your power before this crowd disperses." Qays says: By Allah, we had not yet dispersed when his mount threw him down, and he fell on his head onto those stones, so that his skull split open and he died on the spot.
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim).

It is narrated from Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) made this supplication for me: 'Allahumma saddid ramyatahu, wa ajib da'watahu' (O Allah, make his shot true and answer his supplication).
Yahya bin Hani' al-Shajari is alone in narrating this hadith, and he is a trustworthy Shaykh from the people of Madinah.

It is narrated from Sa'id bin al-Musayyib that he said: I was sitting with Sayyiduna Sa'd (may Allah be pleased with him) in the market when a man named al-Harith bin Barsa' came and said to him: O Abu Ishaq! I was just now with Marwan, and I heard him saying: "This wealth is our wealth; we give it to whomever we wish." On hearing this, Sayyiduna Sa'd (may Allah be pleased with him) raised his hand and said: "Shall I then supplicate (against you)?" Marwan leapt from his seat, rushed towards him, embraced him and said: "O Abu Ishaq! I adjure you by Allah not to supplicate; indeed it is only the wealth of Allah."

Sa'id bin al-Musayyib narrates from Sayyiduna Sa'd (may Allah be pleased with him) that al-Harith bin al-Barsa' came to him in the market and said to him: O Abu Ishaq! I heard Marwan claiming that the wealth of Allah is his own wealth; he gives it to whomever he wishes and withholds it from whomever he wishes. Sayyiduna Sa'd (may Allah be pleased with him) asked: "Did you yourself hear him say this?" He said: Yes. Sa'id says: Then Sayyiduna Sa'd (may Allah be pleased with him) took my hand and the hand of al-Harith until he reached Marwan, and asked: "O Marwan! Do you claim that the wealth of Allah is your wealth, that you give it to whomever you wish and withhold it from whomever you wish?" He said: Yes. He said: "Then I will supplicate," and Sayyiduna Sa'd (may Allah be pleased with him) raised his hands. At that Marwan sprang towards him and said: "I adjure you by Allah not to supplicate; it is the wealth of Allah; He gives it to whomever He wishes and withholds it from whomever He wishes."