Hadith
Sayyiduna Anas 
reports that
Rasulullah :saw: said,
‘Verily, the example of the Ulama on the earth is like the stars in the
sky, they are a means of guidance in the darkness of the land and sea.
When the stars are extinguished, the roadfarers are misled.’
(Musnad Ahmad vol.3 pg.157 Hadith12537)
** Commentary
Hafiz ibn Rajab Hambali [ra] while commenting on this Hadith states
that the comparison of the Ulama with the stars is in 3 aspects:
a) The stars are an adornment for the skies, similarly, the Ulama are
the beauty of the earth.
b) The stars are guides for the travellers, similarly, the Ulama are
guides of mankind.
c) Occasionally, Allah Ta’ala shoots a star at the Shayateen,
similarly, the Ulama are the ammunition against Shaytaan’s mischief.
(Majmoo al-Rasaail ibn Rajab vol.1 pgs.14-15)
In this day and age, when human morals are being disfigured under the
banner of liberation and democracy, it would only be the Ulama who would be appropriately equipped to physically combat these forces of baatil (evil) who strive to distort the prestine religion of Islam, whether
these distortions are working from within or not.
This is what makes it more essential for every community or household
to have an Aalim in their midst. If one is unable to do so, then he
should follow the advice of Sayyiduna Abdullah ibn Mas’ood and Sayyiduna Ali [radhiallaahu anhumaa] who have stated that,
‘Be an Aalim or one who strives to become one. If you cannot do so,
then at least have love for the Ulama and do not hate them.’
(Ibid pg.31; Mu’jamul Kabeer; Hayaatus Sahaaba vol.3 pg.243) **