Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: When the Prophet (peace and blessings be upon him) bade farewell to someone, he would take his hand and would not let go of his hand until the other person himself let go of the hand of the Prophet (peace and blessings be upon him).
Imam al-Bazzar recorded this narration; its chain contains a narrator, Yazid bin Abd al-Rahman bin Umayyah, whom I do not know.
Imam al-Tabarani recorded this narration in al-Mu'jam al-Awsat; its chain contains a narrator, Ibn Abi Sulaym, who is a mudallis; the remaining narrators of this narration have been declared trustworthy.