Musnad Ahmad 25:495

Ubaydah narrated to us, Mansur narrated to me, from Mujahid, from Tawus, from Ibn Abbas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said on the day of the conquest of Makkah: "Indeed, this city is sacred. Allah made it sacred the day He created the heavens and the earth. So it is sacred, made sacred by Allah until the Day of Resurrection. Fighting in it was not made lawful for anyone before me, and it will not be made lawful for anyone after me until the Hour is established. It was only made lawful for me for an hour of the day. So it is sacred, made sacred by Allah (Mighty and Majestic is He) until the Hour is established. Its thorns must not be cut, its fresh grass must not be mowed, its game must not be startled, and its lost property must not be picked up except by one who announces it." He said: Al-Abbas said—and he was from the people of the city, and he knew what they could not do without—: "Except for *idhkhir* (lemon grass), O Messenger of Allah, for they cannot do without it; it is for their graves and their houses." He said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Except for *idhkhir*."