Al-Matalib al-'Aliyah 3614 — Surah al-Anfal

It is narrated from al-Qasim bin Muhammad (may Allah have mercy on him) that a man asked Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) about nafl (that is, the additional grant from the spoils of war). He replied: "The horse used in fighting is part of the nafl, and the salab (that is, the personal belongings and weapons of a slain enemy) is also part of the nafl." The narrator said that the man repeated the same question again, so Sayyiduna Ibn Abbas (may Allah be pleased with them both) said (expressing his displeasure at this needless repetition): "This conduct of yours is exactly like the act of Sabigh (bin Isl) whom Sayyiduna Umar (may Allah be pleased with him) beat (as a penalty for similar needless and mischief-making questions)."
The chain of this hadith is sahih (authentic). Imam Abu Dawud recorded it (hadith no. 2741) and Imam Ahmad (hadith no. 3067). This narration points to the blameworthiness of needless repetition and excessive questioning in gatherings of knowledge.