Acceptance of Islam

Sa'd was among the leading figures among the Ansar, as Muhammad had called the people of Aws and Khazraj from Medina who converted to Islam. He converted at the hands of Mu'sab ibn Umair. His conversion led to the immediate conversion of his entire subtribe of the Aus, the Banu Abdul-Ashhal:

"The leader whom his people follow has come to you" As'ad said Mus'ab. So Mus'ab said to him what he had said to Usayd, Sa'd stuck his lance into the ground, and sat down. The same thing happened again [ie. Conversion to Islam] and he went to his people's meeting place accompanied by Usayd [who had converted earlier]. When they saw him coming they said: "We swear by Allah, Sa'd has returned with a different impression." And when he reached them he asked them how they knew what had happened to him. They replied "You are our Chief, the most active in our interests, the best in your judgement, and the most fortunate in leadership." He then said: "I will not speak to a man or a woman among you until you believe in Allah and his Apostle." As a result every man and woman among the Banu Abdul-Ashhal joined Islam.^[3]

Confrontation with Abu Jahl and start of Badr hostilities

Prior to the Battle of Badr, Sa'd had visited Mecca once to perform his Umrah with his non-Muslim friend Umayyah ibn Khalaf, when they came across Abu Jahl. They had an argument, and as it became heated, Sa'd threatened Abu Jahl with preventing his safe passage through Medina if he stopped the Muslims from performing pilgrimage in Mecca. Narrated 'Abdullah bin Mas'ud:

From Sa`d bin Mu`adh: Sa`d bin Mu`adh was an intimate friend of Umaiya bin Khalaf and whenever Umaiya passed through Medina, he used to stay with Sa`d, and whenever Sa`d went to Mecca, he used to stay with Umaiya.

When Allah's Messenger arrived at Medina, Sa`d went to perform `Umra and stayed at Umaiya's home in Mecca. He said to Umaiya, "Tell me of a time when (the Mosque) is empty so that I may be able to perform Tawaf around the Ka`ba." So Umaiya went with him about midday. Abu Jahl met them and said, "O Abu Safwan! Who is this man accompanying you?" He said, "He is Sa`d." Abu Jahl addressed Sa`d saying, "I see you wandering about safely in Mecca in spite of the fact that you have given shelter to the people who have changed their religion (i.e. became Muslims) and have claimed that you will help them and support them. By Allah, if you were not in the company of Abu Safwan, you would not be able to go your family safely." Sa`d, raising his voice, said to him, "By Allah, if you should stop me from doing this (i.e. performing Tawaf) I would certainly prevent you from something which is more valuable for you, that is, your passage through Medina." On this, Umaiya said to him, "O Sa`d do not raise your voice before Abu-l-Hakam, the chief of the people of the Valley (of Mecca)." Sa`d said, "O Umaiya, stop that! By Allah, I have heard Allah's Messenger predicting that the Muslim will kill you." Umaiya asked, "In Mecca?" Sa`d said, "I do not know." Umaiya was greatly scared by that news.

When Umaiya returned to his family, he said to his wife, "O Um Safwan! Don't you know what Sa`d told me?" She said, "What has he told you?" He replied, "He claims that Muhammad has informed them (i.e. companions) that they will kill me. I asked him, 'In Mecca?' He replied, 'I do not know." Then Umaiya added, "By Allah, I will never go out of Mecca." But when the day of (the Ghazwa of) Badr came, Abu Jahl called the people to war, saying, "Go and protect your caravan." But Umaiya disliked to go out (of Mecca). Abu Jahl came to him and said, "O Abu Safwan! If the people see you staying behind though you are the chief of the people of the Valley, then they will remain behind with you." Abu Jahl kept on urging him to go until he (i.e. Umaiya) said, "As you have forced me to change my mind, by Allah, I will buy the best camel in Mecca. Then Umaiya said (to his wife). "O Um Safwan, prepare what I need (for the journey)." She said to him, "O Abu Safwan! Have you forgotten what your Yathribi brother told you?" He said, "No, but I do not want to go with them but for a short distance."

So when Umaiya went out, he used to tie his camel wherever he camped. He kept on doing that till Allah caused him to be killed at Badr.^[4]

Battle of Badr

The Muslims originally expected a much smaller Meccan force, but were surprised by the large Meccan Army so refugee Prophet Muhammad called Shura:

When the Muslim army missed the caravan and the Quraysh army, between nine hundred and one thousand strong, helmeted and drawing closer, Abu Bakr stood up and said something good.

Several more Muhajirun also spoke, all the while the Messenger of Allah repeated: "advise me, O Muslims!", inquiring of what the Ansar, the majority then, had to say.

Then Sa`d bin Mu`adh said, "It looks like you mean us, O Messenger of Allah! By He Who has sent you with the Truth! If you seek to cross the sea and went in it, we will follow you, and none among us will remain behind. We will not hate for you to lead us into battle against the enemy tomorrow. We are patient in war, vicious in battle. May Allah allow you to witness from our efforts what comforts your eyes. Therefore, march forward with the blessing of Allah."

The Messenger of Allah was pleased with the words of Sa`d and was encouraged to march on.

^[5]

Battle of Uhud

Sa'd was one of the few companions who remained on the battlefield, when the Meccans led by Khalid bin Walid counterattacked and he continued to fight on until he was finally forced to retreat away from the Meccans. In fact, Sa'd was the last Muslim Mus'ab ibn 'Umair met (Sa'd by that time had disengaged the Meccans) when he chided other Muslims for retreating and ferociously attacked the Meccans resulting in his brutal martyrdom at the hands of the Meccans.^[6] He later met up with Muhammad and was part of the small contingent Muslims defending him.

Sa'd's brother 'Amr and his stepson (nephew) al-Harith ibn Aws were both among those who were killed at Uhud.^{[1]: 342–343}

Battle of Trench and Qurayza

After the Battle of the Trench in 627 (5 AH), when Medina was unsuccessfully besieged by the Meccan army, the Banu Qurayza had treacherous dealings with the enemy.^[7] Later the Muslims laid siege to their stronghold and the Banu Qurayza surrendered.

Several members of the Banu Aws pleaded for their old Jewish allies and agreed to Muhammad's proposal that one of their chiefs should judge the matter. The Banu Qurayza themselves appointed Sa'd, and declared they would agree with whatever was Sa'd's verdict.^[8][9] The verdict for the Banu Qurayza, a Jewish clan in Medina, was consistent with the Old Testament^{[note 1]} and some scholars claim the verdict was based on Deutoronomy 20:12-14.^[10][11]

Some people (i.e. the Jews of Bani bin Quraiza) agreed to accept the verdict of Sad bin Muadh so the Prophet sent for him (i.e. Sa'd bin Muadh). He came riding a donkey, and when he approached the Mosque, the Prophet said, "Get up for the best amongst you." or said, "Get up for your chief." Then the Prophet said, "O Sa'd! These people have agreed to accept your verdict." Sa'd said, "I judge that their warriors should be killed and their children and women should be taken as captives." The Prophet said, "You have given a judgment similar to Allah's Judgment (or the King's judgment)."^[12]

Early Arabic rock inscription

A rock inscription was discovered in mount Sela; In the fourth and fifth line appear the words, "I am Muhammad ibn Abdullah" and that is the full name of the prophet Muhammad as his father was Abdullah. In the eighth line is the name, " I am Salman the (?)". In the twelfth line is the phrase "I am Sa'd bin Mu'adh", and finally on the fifteenth line "I am Ali ibn Abu Talib".> As it is known that Saad ibn Muad died in 627, the inscription can not be from a later era, further the location of this inscription may hint that it was meant to commemorate the Muslim victory in the battle.