مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3704
Musnad of Abdullah bin Mas'ood
It was narrated from 'Abdullah bin Mas'ood from the Prophet (ﷺ) that he said: "A man may continue to tell the truth and endeavour to be truthful until he is recorded as a speaker of truth or he may continue to tell lies and endeavour to tell lies until he is recorded as a liar."
Musnad Ahmad 3727Its isnad is saheeh, al-Bukhari (6094) and Muslim (2607)]