It wasnarrated from Ka'b bin 'Ujrah that the Messenger of Allah(ﷺ)saw a man who had interlocked his fingers during the prayer, sotheMessenger of Allah (ﷺ) separated his fingers. (PT)
English reference (PT): Vol. 1, Book 5, Hadith 967 (PT)
Arabic reference (PT): Book 5, Hadith 1020 (PT)