"إذا كانَ أحدُكم في المسجدِ فلا يُشبِّكْ أصابَعه فإِنَّه في صَلَاةٍ".
Messenger of Allah (S) said: "When one of you performs Wudu and does so well, then he leaves intending to go to the Masjid, then let him not intertwine his fingers, for indeed he is in Salat."
أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ إِذَا تَوَضَّأَ أَحَدُكُمْ فَأَحْسَنَ وُضُوءَهُ ثُمَّ خَرَجَ عَامِدًا إِلَى الْمَسْجِدِ فَلاَ يُشَبِّكَنَّ بَيْنَ أَصَابِعِهِ فَإِنَّهُ فِي صَلاَةٍ
[Machine] I heard the Messenger of Allah ﷺ saying, "When one of you performs ablution and then goes to the mosque, he should not interlace his fingers, for he is in prayer."
سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ «إِذَا تَوَضَّأَ أَحَدُكُمْ ثُمَّ أَتَى الْمَسْجِدَ فَلَا يُشَبِّكْ بَيْنَ أَصَابِعِهِ فَإِنَّهُ فِي صَلَاةٍ»
AbuThumamah al-Hannat said that Ka'b ibn Ujrah met him while he was going to the mosque; one of the two (companions) met his companion (on his way to the mosque) And he met crossing the fingers of my both hands. He prohibited me to do so, and said: The Messenger of Allah ﷺ has said: If any of you performs ablution, and performs his ablution perfectly, and then goes out intending for the mosque, he should not cross the fingers of his hand because he is already in prayer. (Using translation from Abū Dāʾūd 562)
"إذَا توضَّأ أحدُكمْ فأحْسن وُضُوءَه ثمَّ خرج عامِدًا إلى المسْجِد، فلا يُشبِّكنَّ أصابِعَه ، فإِنَّه في صَلاةِ" .