Al-Matalib al-'Aliyah 843 — The concession to weep over the deceased

It is narrated from Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) that on that day (on the death of Sayyiduna Sa'd bin Mu'adh (may Allah be pleased with him)) the Messenger of Allah (peace and blessings be upon him) drew up both his blessed knees. Meanwhile an angel entered but found no place to sit, so I made room for him. During this, Umm Sa'd (that is, the mother of Sayyiduna Sa'd bin Mu'adh (may Allah be pleased with him)) was weeping over him and reciting these verses: "Woe to the mother of Sa'd at the parting from Sa'd! He was the embodiment of excellence and nobility; after the mention of his favours and greatness, he sacrificed his youth (in the path of Allah)." Then the Messenger of Allah (peace and blessings be upon him) said: "Every woman who weeps (over the dead) lies (because of exaggeration), except Umm Sa'd."
The chain of this hadith is hasan (good); Imam Ishaq bin Rahwayh recorded it in his Musnad, and Imam al-Hakim also graded it sahih (authentic).