مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3923
Musnad of Abdullah bin Mas'ood
It was narrated that 'Abdullah said: The Messenger of Allah (ﷺ) said: "The believers is not given to cursing people, he does not malign people, and he is not foul-mouthed or rude.”
Musnad Ahmad 3948Its isnad is saheeh]