May Allah reject these hands! I have seen the Messenger of Allah ﷺ on the pulpit gesturing no more than this pointing with his forefinger.  

عُمَارَةُ قَبَّحَ اللَّهُ هَاتَيْنِ الْيَدَيْنِ قَالَ زَائِدَةُ قَالَ حُصَيْنٌ حَدَّثَنِي عُمَارَةُ قَالَ لَقَدْ رَأَيْتُ رَسُولَ اللَّهِ ﷺ وَهُوَ عَلَى الْمِنْبَرِ مَا يَزِيدُ عَلَى هَذِهِ يَعْنِي السَّبَّابَةَ الَّتِي تَلِي الإِبْهَامَ  

I never saw the Messenger of Allah ﷺ raising his hands and praying on the pulpit or otherwise. But I saw him saying (doing) this way, and he would point with his forefinger making a circle by joining the middle finger with his thumb.  

مَا رَأَيْتُ رَسُولَ اللَّهِ ﷺ شَاهِرًا يَدَيْهِ قَطُّ يَدْعُو عَلَى مِنْبَرِهِ وَلاَ عَلَى غَيْرِهِ وَلَكِنْ رَأَيْتُهُ يَقُولُ هَكَذَا وَأَشَارَ بِالسَّبَّابَةِ وَعَقَدَ الْوُسْطَى بِالإِبْهَامِ