Abdullah bin Amr (may Allah be pleased with him) narrates that the Prophet Muhammad (peace and blessings be upon him) said: "O Abdullah bin Amr! Do not be like that person who used to offer voluntary prayers at night but then abandoned the night prayer." (Imam Ibn Hibban, may Allah have mercy on him, says:) In this narration, there is evidence that it is permissible for a person to say something about another person in his absence, which, if that person were to hear it, would make him sad, as long as the intention of the speaker is not to disparage him but rather to warn someone else in some regard.