It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: Sometimes a person utters a word that pleases Allah, and he does not consider it to be of any significance, but as a result of that one word, Allah raises his ranks on the Day of Judgment. And sometimes a person utters a word that displeases Allah, and he does not care about it, but as a result of that one word, he will keep falling into Hell on the Day of Judgment.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 8411
Hadith Gradingحکم دارالسلام:حديث صحيح، خ: 6478، فى هذا الإسناد عبدالرحمن، فيه كلام ينزله عن رتبة الصحيح