Musnad Ahmad 1424

Sufyan bin Wahb al Khawlani said: When we conquered Egypt without a peace deal (i.e., by force), az-Zubair bin al-"Awwam (رضي الله عنه) stood up and said: “O "Amr bin al "As, divide the land.” "Amr said: “I shall not divide it.” az-Zubair (رضي الله عنه) said: “By Allah, you will divide it as the Messenger of Allah (ﷺ) divided Khaibar!” ‘Amr said: “By Allah, I shall not divide it until I write to Ameer al-Mu"mineen.” So he wrote to "Umar (رضي الله عنه) and "Umar wrote back to him (saying}, Leave it so that the third generation (i.e., the offspring of the foetuses currently in their mother"s wombs) may use the income from it to go out on campaign for the sake of Allah.