Hazrat Umme Sulaim (ra) was a very obedient Companion of the Holy Prophet (sas) and tried her best to follow all of his commandments. One lady narrates that the Holy Prophet (sas) took their bai‘at [pledge of initiation] on the condition that they would not wail over the dead. This pledge was fulfilled by five women, one of whom was Hazrat Umme Sulaim (ra).1
1 Saheeh Bukhaari, Kitaabul-Janaa’izi, Baabu Maa Yunhaa minan-Nauhi wal-Bukaa’i waz-zajri ‘an zaalik, Hadith no. 1306.