From Sahih Bukhari (Hadith 5294):
Narrated Abu Huraira: Abul Qasim (the Prophet (ﷺ) ) said, "There is an hour (or a moment) of particular significance on Friday. If it happens that a Muslim is offering a prayer and invoking Allah for some good at that very moment, Allah will grant him his request." (The sub-narrator placed the top of his finger on the palm of the other hand between the middle finger and the little one)
Reference: Bukhari 5294