When should the people get up for the Salat (prayer) if they see the Imam (the person leading Salat) during the Iqama?

Sahih al-Bukhari · Book 10 · Hadith 637

حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا هِشَامٌ، قَالَ كَتَبَ إِلَىَّ يَحْيَى عَنْ عَبْدِ اللَّهِ بْنِ أَبِي قَتَادَةَ، عَنْ أَبِيهِ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ إِذَا أُقِيمَتِ الصَّلاَةُ فَلاَ تَقُومُوا حَتَّى تَرَوْنِي ‏"‏‏.‏

Narrated `Abdullah bin Abi Qatada: My father said. "Allah's Messenger (ﷺ) said, 'If the Iqama is pronounced then do not stand for the prayer till you see me (in front of you).' "