It is narrated about Sayyiduna Abu Musa Ash'ari (may Allah be pleased with him) that when he conquered Tustar, he sent news to Hazrat Umar bin Khattab (may Allah be pleased with him). The messenger found him in a garden. I said the takbir, so Umar (may Allah be pleased with him) also said the takbir. I said the takbir again, and he also said it. When I reached him, I gave him the news of the victory. Umar (may Allah be pleased with him) asked: "Any strange news?" I said: "A man became a disbeliever after accepting Islam." He asked: "Then what did you do?" I said: "We killed him." Umar (may Allah be pleased with him) said: "O Allah! I neither saw it, nor participated in it, nor was I pleased when this matter reached me. I wish you had locked him in a house with mud and sent him a loaf of bread every day; perhaps he would have repented." Then he asked: "What do you do with the forts?" I said: "We get close, and if a stone is thrown, they say, whoever it hits will be killed." Umar (may Allah be pleased with him) said: "I do not like that the conquest of a village should be at the cost of a thousand Muslims' lives."

Sayyiduna Umar bin Khattab (may Allah be pleased with him) sent Sayyiduna Abu Musa Ash'ari (may Allah be pleased with him) to Basra and Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) to Kufa. When Abu Musa conquered Tustar, he wrote to Umar (may Allah be pleased with him) that Tustar should be made subordinate to Basra. Sa'd also wrote that it should be made subordinate to Kufa. The messenger of Abu Musa (Mujazza'ah bin Thawr or Shaqiq bin Thawr) arrived first and met Umar (may Allah be pleased with him). When the messenger saw Umar (may Allah be pleased with him), he said takbeer, and Umar (may Allah be pleased with him) also said takbeer. The messenger said: "O Commander of the Faithful! Should Tustar be included in Basra?" Umar (may Allah be pleased with him) said: "Yes, it is the territory of Basra." Then the messenger gave the letter and informed that a person had become apostate, and we killed him. Umar (may Allah be pleased with him) said: "If only you had imprisoned him for three days and given him a loaf of bread each day, perhaps he would have repented. O Allah! I neither saw, nor ordered, nor was pleased when this news reached me."

Sayyiduna Anas bin Malik (may Allah be pleased with him) says: On the day of Tustar, six people from Banu Bakr bin Wa'il became apostates. I went to Umar bin Khattab (may Allah be pleased with him). He asked: "What happened to those people?" I turned the conversation to something else. Then he asked again. I said: "They were killed." Umar (may Allah be pleased with him) said: "If I had found them, it would have been more beloved to me than the rising of the sun." I said: "Was it necessary to kill them?" He said: "I would have called them back to Islam; if they accepted, fine, otherwise I would have put them in prison."

Ata Khurasani (may Allah have mercy on him) says: Tustar was conquered through a peace treaty, then the people of Tustar reverted to disbelief. The Muhajirun attacked them and married their women, to the extent that children were born to them. I saw their children. Umar ibn al-Khattab (may Allah be pleased with him) ordered that those who could be identified should be returned to their jizya and separated from their masters.

Ibrahim Taimi (may Allah have mercy on him) says: When the Muslims conquered Sawad (Iraq), they said to Umar (may Allah be pleased with him): "Distribute it among us." Umar (may Allah be pleased with him) said: "What will happen to the Muslims who come after you? I fear you will quarrel over water and fight among yourselves." Then Umar (may Allah be pleased with him) kept the people of Sawad on their lands and imposed jizya on them and kharaj on the land, and did not distribute the land.

Mujahid (may Allah have mercy on him) says: "Any city that is conquered by force, if its people accept Islam before the distribution of the spoils of war, then they are free and their wealth belongs to the Muslims."

Sayyiduna Amr bin al-As (may Allah be pleased with him) entered Egypt with three thousand five hundred people. When Umar bin Khattab (may Allah be pleased with him) received this news, he sensed danger and sent Sayyiduna Zubair bin al-Awwam (may Allah be pleased with him) with twelve thousand people, who, after joining Amr bin al-As (may Allah be pleased with him), participated in the conquest of Egypt. Sayyiduna Zubair (may Allah be pleased with him) had his share allotted in Fustat.