I am one of the arrows of Islam, and after Allah, you are the one to shoot it and collect (the arrows). So choose the strongest, most pious and best of them and use it. [ltmam al Wafa’ bi Sirat al Khulafa’, p. 55]
When he came to Madinah, Abu Bakr رضي الله عنه told him to stay outside Madinah and camp until he had urged the people to join him, then he sent him with an army to Syria. [Al Azdi: Futuh al Sham, p. 48-51]
During the Battle of Yarmuk, ‘Amr رضي الله عنه was in charge of the right flank and his participation had a great impact on the Muslim victory.
After the death of Abu Bakr رضي الله عنه, ‘Amr رضي الله عنه remained in Syria and played an effective role in the Islamic conquest of Syria. Along with Shurahbil ibn Hasanah رضي الله عنه, he conquered Bis, Tiberias and Ajnadin. [Tarikh al Tabari, 3/605; Ibn al Athir: al Kamil, 2/498]
He also conquered Gaza, al Ludd (Lad), Yubna, ‘Amwas (Emmaus), Bayt Jibrin, Yafa (Jaffa), Rafah and Jerusalem. Not only did ‘Amr رضي الله عنه conquer Syria; he also conquered famous cities in Egypt. ‘Umar ibn al Khattab رضي الله عنه issued instructions to ‘Amr ibn al ‘As رضي الله عنه, after he had finished conquering Syria, to march to Egypt with the troops who were with him. He set out until he reached al ‘Arish and conquered it, and he also conquered al Farma, al Fustat, the Fortress of Babylon, ‘Ayn Shams, al Fayyum, al Ashmunin, Akhmim, al Bashrud, Tanis, Dimyat (Damietta), Tuna, Daqhalah, Alexandria and other North African cities such as Barqah, Zuwaylah, and Tripoli. [Siyar A’lam al Nubala’, 3/70; Al Qiyad al ‘Askariyyah fi ‘Ahd al Rasul, p. 634-942]
The report is da‘eef (weak) and is not saheeh (sound):
Ibn Katheer (رحمه الله) said: It was narrated to us via Ibn Luhay‘ah from Qays ibn al-Hajjaj from someone who told him: When Egypt was conquered, its people came to ‘Amr ibn al-‘As (may Allah be pleased with him) and said to him: O Ameer, this Nile of ours is used to something and cannot flow unless it is done. He said: What is that? They said: On the twelfth night of this month, we take a young girl from her parents, and we placate her parents, then we dress her in jewellery and the finest garments there can be, then we throw her into this Nile.
‘Amr (رضي الله عنه) said to them: This is something that cannot happen in Islam; Islam erases that which came before it (of bad customs).
So they stayed for a while, during which the Nile did not flow at all, neither a little nor a lot, until they thought of leaving. Then ‘Amr (رضي الله عنه) wrote to ‘Umar ibn al-Khattab (رضي الله عنه), telling him about this. He wrote to him, saying: You did the right thing. I am sending you a piece of paper with my letter; throw it into the Nile.
When his letter came, ‘Amr (رضي الله عنه) took the piece of paper on which was written:
“From the slave of Allah ‘Umar, Ameer al-Mumineen, to the Nile of the people of Egypt.
To proceed: If you only flow on your own initiative, then do not flow, for we have no need of you. But if you only flow on the command of Allah, the One, the Subduer, and He is the One Who causes you to flow, then we ask Allah, may He be exalted, to make you flow.”
He threw the paper in the Nile and by Saturday morning, Allah had caused the Nile to flow (to a depth or width of) sixteen cubits in one night, and Allah put an end to this particular custom of the people of Egypt until today. [al-Bidayah wa’n-Nihayah, 7/114-115]
NOTE: Similar reports were also narrated by Ibn ‘Abd al-Hakam in Futooh Misr, p. 165; al-Lalkai in Sharh I‘tiqad Ahl as-Sunnah, 6/463; Ibn ‘Asakir in Tareekh Dimashq, 44/336; Abu’sh-Shaykh in al-‘Azamah, 4/1424, via Ibn Luhay‘ah.
This is a da‘eef isnad (weak chain of narration) that is not saheeh, and this report cannot be proven with such an isnad. Ibn Luhay‘ah – whose full name was ‘Abdullah ibn Luhay‘ah ibn ‘Uqbah – is da ‘eef as he used to get mixed up, and in addition to that he is mudallis (one who narrates from someone he met something he did not hear). See at-Tahdheeb, 5/327-33; Mizan al-I‘tidaal, 2/475-484