Shaikh Zaid al Madkhali said in a book titled: Al Kenz al Thameen (The Precious Treasure)
بسم الله الرحمن الرحيم
It is upon the people of knowledge of this Ummah – the inheritors of the generous Prophets, the great Messengers, the beauty and stars of the earth – it is upon them to prepare themselves to spread the guidance of Allah; that which Allah guides whom He wills from amongst His servants all over the world, North to South, East to West! It is upon them not to hesitate in exerting all means that can be used to propagate and spread the religion. They should be vigorous in benefitting the people with good so that groups and individuals can live good, blessed lives. (By way of this knowledge and propagation) the disbeliever will enter into Islam, the headless person will awaken, the ignorant person will learn, the confused person will gain insight, and the open sinner will become shy from Allah! How many people are affected by these calamities these days, and how few are the doctors who have the ability to treat their wounds, and cure their illnesses of desires and doubts, while seeking the face of Allah and His Jennah!
Translation by: Mustafa George DeBerry
Source: Al Kenz al Thameen pg. 15-16 by Shaikh Zaid bin Muhammad al Madkhali (may Allah have mercy on him)