It is reported that Abū Muslim Al-Khawlānī – Allāh have mercy on him – said:

The example of the scholars on earth is that of the stars in the sky: when they appear, the people are guided (they navigate using the stars), but when they disappear, the people get confused and lost.

Al-Bayhaqī, Al-Madkhal ilā Al-Sunan Al-Kubrā #287