In The Name of Allah, The Most Merciful, The Bestower of Mercy.

Aishah, may Allah be pleased with her, narrated:

“There was no traite more hated to Allah’s Messenger, peace and blessings of Allah be upon him, than lying. A man would speak based on lies in the presence of the Prophet, peace and blessings of Allah be upon him, and he would not be content until he knew that he had repented.” [Sahih Tirmidhi 1973]

Abdur-Raḥmān ibn Yazīd ibn Jābir said:

Once we were with Rajāʾ ibn Ḥaywah, then we began reminding one another about showing gratitude for (Allah’s) blessings, so he said: ‘There is no one who can truly fulfill gratitude (to Allah) due to blessings’. And behind us there was a man with a cloak over his head, who said: ‘Not even the Amīr al-Muʾminīn)?’ We said: ‘We said: ‘The Amīr al-Muʾminīn has not been mentioned (specifically) here, rather, we are speaking in general — about any person!’ He (Abdur Rahman) said: ‘Our attention was diverted from him, then Rajā turned to notice his presence but could not see him, so he said, ‘The one who was wearing the cloak came to you. If you are called to swear by Allah, swear by Allah (truthfully)’.

He (Abdur Rahman) said: ‘It was not long before a guard of his (i.e. the Amīr al-Muʾminīn) approached him’. He (the Amīr al-Muʾminīn) said: ‘O Rajā! The Amīr al-Muʾminīn is mentioned, and you did not defend him (or support him)?’ He (Rajā) said: ‘O Amīr al-Muʾminīn! What is the matter about?’ He said: ‘You mentioned showing gratitude for (Allah’s) blessings and said: ‘There is no one who can truly fulfill gratitude (to Allah) due to blessings’ and it was said to you, ‘Not even the Amīr al-Muʾminīn?’ And you said: ‘Amīr al-Muʾminīn is just a man like others!’ Rajāʾ replied: ‘That did not happen'(i.e. you were not specified as the one intended regarding this discussion). He said, ‘By Allah'(i.e. you did not mean this?) Rajāʾ said: ‘By Allah’. So, he (Amīr al-Muʾminīn) commanded that the man who transmitted the (rumour) be whipped seventy lashes. I exited and the man was covered in his own blood. Then he said: ‘You are Rajā ibn Ḥaywah and this happens because of you?!’ He (Rajā) said: ‘Seventy lashes on your back are better than (spilling) a believer’s blood’. Ibn Jābir said: ‘Thereafter, whenever Rajā sat in a gathering, he would say while looking around, ‘Beware of the man who wore the cloak'”. [1]

[1] Siyar Aʿlām al-Nubalāʾ. 4/561