Sahih Adab al-Mufrad

Sayyiduna Abu Darda’ (may Allah be pleased with him) narrates from the Prophet (peace and blessings of Allah be upon him) that he said: “Whoever has been given his share of gentleness has been given his share of goodness, and whoever is deprived of his share of gentleness has been deprived of his share of goodness. On the Day of Resurrection, the heaviest thing in the believer’s scale will be good character, and indeed Allah dislikes the foul-mouthed, ill-mannered person.”