«كان إذا ودع رجلا أخذ بيده فلا يدعها حتى يكون الرجل هوالذي يدع يده ويقول: أستودع الله دينك وأمانتك وخواتيم عملك»
It was the practice of the Prophet (peace and blessings be upon him):
"When he (peace and blessings be upon him) bade farewell to a man, he would take hold of his hand and would not let go of it until the man himself withdrew his hand, and he (peace and blessings be upon him) would say: 'Astawdi'ullaha dinaka wa amanataka wa khawatima 'amalik' (I entrust to Allah your religion, your trust and the final outcome of your deeds)."
Hadith Referenceصحیح الجامع الصغیر / حرف الكاف / 4795
Hadith Gradingالألبانی:صحيح
Hadith Takhrij[حم ت ن هـ ك] عن ابن عمر. الصحيحة ١٤: المشكاة ٥٨٢٤.