Jundub (may Allah be pleased with him) narrated: The Messenger of Allah (peace be upon him) said: "The example of a scholar who teaches people goodness and forgets himself is like a lamp which illuminates for the people but burns itself." (1)
Lessons gained from the Hadith:
1- The excellence of knowledge as being a light for scholars and the people when a scholar acts according to his knowledge and teaches the people.
2- Severe threat to those who do not act according to their knowledge.
3- Exhortation to match between words and actions. Allah (may He be Exalted) says: "O you who believe! Why do you say that which you do not do?" * Most hateful it is with Allâh that you say that which you do not do." [Surat As-Saf: 2- 3].
4- The negligence of a scholar is not a barrier to benefit from his knowledge, but his negligence will not harm anyone but the scholar himself.
(1) Reported by At-Tabarany in Al Mu`jam Al Kabir 2/178, No. (1681) and Al Albany graded it as good. See: Sahih At-Targhib wat-Tarhib, 1/ 31, No. (131).