Mention was made to Allah's Messenger (peace be upon him) of two
persons: the one being a devout, and the other being a scholar. Thereupon
Allah's Messenger (peace be upon him) said: 'The superiority of the scholar
over the devout is like my superiority over one who is of hte lowest rank
amongst you.' Then Allah's Messenger (peace be upon him) said: 'Verily (for
the scholars) Allah and His angels, the dwellers of the Heavens and of the
Earth, even an ant in its hole and fish (in the depth of water) invoke blessings
on one who teaches people goodness.'
Hadith 213, Al-Tirmidhi
Al-Tirmidhi also relates:
Allah's Messenger (peace be upon him) said: 'A single scholar of religion
is more formidable againt satan than a thousand devout people.'