Do not rush to praise a person

Harasha ibn al-Hurr said:

“Once a man appeared as a witness before ‘Umar ibn al-Khattab (may Allah be pleased with him), and ‘Umar said to him: “I do not know you, but it will not harm you that I do not know you, but bring him who will testify for you.”

Then one of the people present said, “I know him!”
‘Umar asked: “How is he known to you?”
He replied: “Justice and dignity.”

‘Umar asked: “Is he a neighbor who lives next to you, whom you see both at night and during the day, when he comes and when he leaves?”
He replied: “No.”

‘Umar asked: “Do you have commercial and financial relations with him, in which the piety of a person is recognized?”
He said, “No.”

‘Umar again asked: “Is he your companion on the path in which good character is known?”
He again replied, “No.”

Then ‘Umar said to him, “You don’t know him!” and then he said to that witness, “Come with someone who knows you.”

al-Bayhaqi in al-Kubra (10/125), Hafiz Ibn Kathir and Sheikh al-Albani confirmed the authenticity of this report. ” “Irua al-galil” (2637).

Also ‘Umar ibn al-Khattab (may Allah be pleased with him) said: “Do not delude yourself with prayer or fasting of a person, but look at the one who speaks the truth; who shows reliability when he is trusted; and who, having desired the sinful, shows piety!”
al-Bayhaqi in al-Sunan al-kubra (6/288). Hafiz Ibn Hajar confirmed the authenticity. See al-Matalib al-‘aliyah (2631).