Narrated Sa'd ibn AbuWaqqas:

The Prophet ﷺ passed by me while I was supplicating by pointing with two fingers of mine. He said: Point with one finger; point with one finger. He then himself pointed with the forefinger.

حَدَّثَنَا زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا أَبُو مُعَاوِيَةَ، حَدَّثَنَا الأَعْمَشُ، عَنْ أَبِي صَالِحٍ، عَنْ سَعْدِ بْنِ أَبِي وَقَّاصٍ، قَالَ مَرَّ عَلَىَّ النَّبِيُّ ﷺ وَأَنَا أَدْعُو بِأُصْبُعَىَّ فَقَالَ
" أَحِّدْ أَحِّدْ " . وَأَشَارَ بِالسَّبَّابَةِ .