Sayyiduna Amr bin Hurayth (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) used to place the right hand over the left hand in the prayer, and sometimes he would also touch his beard during the prayer.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3430
(a) It is narrated from Sayyiduna Amr bin Hurayth (may Allah be pleased with him) that the Prophet (peace and blessings be upon him), while praying, would sometimes also take hold of his beard.
(b) Ibrahim al-Nakha'i (may Allah have mercy on him) said: It used to be said: In the prayer, touch the beard once, or do not touch it even once but leave it.
(c) Imam al-Bayhaqi (may Allah have mercy on him) said: This is similar to what is reported about touching the pebbles once.
It has also been narrated through another, weak, route, and in one of them it is said: without fidgeting.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3431
Ishaq bin Musa al-Khatmi said: I heard al-Walid bin Muslim say: I heard Isa bin Abdullah bin al-Hakam bin al-Nu'man bin Bashir (may Allah be pleased with him), and he reported from Nafi', but his hearing from him is not established.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3432
(a) It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) would sometimes, out of need, place his blessed hand on his blessed beard during the prayer.
(b) It is reported from Ibrahim (al-Nakha'i) (may Allah have mercy on him): Touch the beard once or so, and that is all.
It has also been narrated through another, weak, route, from the hadith of Abu Dharr. Abu Ahmad (Ibn Adi) (may Allah have mercy on him) said: Most of what this Isa al-Qaddah narrates is not corroborated.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3433
Hadith Gradingمحدثین:ضعيف جدا
Hadith Takhrij«ضعيف جدا۔ اخرجه ابن عدي في الكامل 5/ 253»