Is it better to stand for the rows when the muezzin begins the Iqama, or when he says, "Qad Qamat As-Salat (The prayer has begun)"?

The matter is broad concerning the time when worshipers stand for prayer during the iqamah. They may stand at the beginning of the iqamah, in its middle, or after it has finished. The majority of scholars hold that if the Imam is in the mosque, they should not stand until the iqamah is completed. Imam Malik stated that the matter depends on people's capability. Al-Hafiz Ibn Hajar mentioned several opinions on this, including Anas's standing when the muezzin said: "قد قامت الصلاة" (the prayer is about to begin). However, if the Imam is not in the mosque, the majority do not stand until they see him. Sheikh Ibn Uthaymeen explained that the Sunnah did not specify a particular moment for standing, except for the Prophet's saying (peace be upon him): "Do not stand until you see me." So, whenever a person stands, all of that is permissible.