Full Sharh — Riyad as-Salihin 271
عن أنس رضي الله عنه قال: مروا بجنازة، فأثنوا عليها خيراً، فقال النبي صلى الله عليه وسلم الله عليه وسلمى الله عليه وسلم الله عليه وسلم : "وجبت”، ثم مروا بأخرى، فأثنوا عليها شراً، فقال النبي صلى الله عليه وسلمى الله عليه وسلم الله عليه وسلم الله عليه وسلم : "وجبت" فقال عمر بن الخطاب رضي الله عنه: ما وجبت؟ قال: "هذا أثنيتم عليه خيراً، فوجبت له الجنة، وهذا أثنيتم عليه شراً فوجبت عليه النار، أنتم شهداء الله في الأرض” ((متفق عليه)).
English Translation
Anas (May Allah be pleased with him) reported:: Some Companions happened to pass by a funeral procession (bier) and they praised him (the deceased). The Prophet (ﷺ) said, "He will certainly enter it." Then they passed by another funeral procession and they spoke ill of the deceased. The Prophet (ﷺ) said, "He will certainly enter it." `Umar bin Al-Khattab (May Allah be pleased with him) said: "(O Messenger of Allah,) what do you mean by `He will certainly enter it?'' He (ﷺ) replied, "You praised the first person, so he will enter Jannah; and you spoke ill of the second person, so he will enter Hell. You are Allah's witnesses on earth." .
Source
Riyad as-Salihin(رياض الصالحين)
The Book of Visiting the Sick
Hadith Number
271