Do You Really Know Him?

On the authority of Sulaymaan bin Mushir, on the authority of Kharashah bin Al-Hurr, who said: 

"A man bore witness in the presence of 'Umar bin Al-Khattaab-radi Allahu anhu- so 'Umar said to him: 'I do not know you and it does not harm you that I don't know you, but bring me some one who knows you.'  Thus a man said: 'I know him, Oh Chief of the Believers.' [Hence,] Umar said: ' What do you know of him?' [So, the man] said: 'Uprightness.' [So] 'Umar said: 'Is he your your closest neighbor, thus you [came to] know about his night and day, his comings and goings? Hence, the man said: 'No.'  [So] 'Umar said: 'Have you had monetary dealings with him involving daraahim and dananeer,  thus indicating his piety? [Hence] the man said: 'No.' So 'Umar said: 'Has he been your companion on a  journey, thus indicating to you his good character? The man said: 'No.' Consequently, Umar said: 'Then you don't [really] know him.'  So, ['Umar] said to the man [who bore witness]: 'Bring me someone who knows you.' " [Related by Al Bayhaqī and others and it is graded saheeh]