There are four kinds of men. One is who has no tongue and no heart and he is a man of ordinary position, dull and lowly, who does not count on Allah and one who has nothing good in him. He and people like him are the chaff which has no weight, unless Allah covers them with His mercy and guides their heart towards belief in Himself and moves the organs of their body in obedience to Himself. Beware that we do not become one of them and do not entertain them nor mind them nor yet stand among them. These are the people of chastisement and wrath and anger of Allah; they are the inhabitants of fire and its inmates. We seek refuge in Allah from them. You should on the contrary be equipped with Divine knowledge and be among the teachers of good and guides for religion and its leaders and inviters thereto. So beware that you should come to them and invite them to obedience to Allah and warn them against sinning against Allah. Thus you will be a fighter in the cause of Allah and you will be given the rewards of prophets and Messengers of Allah. The Holy prophet (may peace and blessings of Allah be upon him) said to Ali:
If Allah gives guidance to one person through your guiding him, it is better for you than that on which the sun rises.
The other kind of person has got a tongue but no heart; he speaks on wisdom but does not act according to it. He calls people to Allah but himself flees from Him. He abhors defects in others but he himself persists in a similar defect in himself. He shows to others his piety but contends with Allah by committing major sins. And when he is alone he is like a wolf in clothes. Here is a person against whom the Prophet has warned. He has said:
The thing to be most afraid of and which I am afraid of in respect of my followers is the evil learned men.
We seek the refuge of Allah from such learned men. So you should keep away from such a man and run away from him, lest you should be carried away by the sweetness of his talk and then the fire of his sin will burn you and the filth of his inside and heart should kill you.
There is a third kind of man who has a heart but no tongue and he is a believer. Allah has screened him away from His creation and hung round him His curtains and given him an insight into the blemishes of his own self and enlightened his heart and made him aware of the mischiefs of mixing with people and of the evil of talking and speaking and who has become sure that safety is in silence and retirement in a corner, as the Prophet (sallallahu'alayhi wa sallam) has said: "Whoever kept silent attained to salvation." And as further he has said: "Surely the service of Allah consists of ten parts, nine of which are in silence." Thus this man is a friend of Allah in His secrets, protected, possessing safety and plenty of intelligence, companion of the Beneficent Allah, blessed with His favors and as for good, everything good is with him. So mind, you must keep company with such a man and mix with him and render him service and endear yourself to him by fulfilling the needs which he may feel, and providing him with things which will give ease and comfort. If you do these things Allah will love you and choose you and include you in the company of His friends and pious servants together with His blessings, if it pleases Him.
The fourth kind of man is one who is invited to the world invisible, clothed in dignity, as it is related in the tradition:
Whoever learns and acts upon his learning and imparts it to others is invited to the world invisible and made great.
Such a man is possessed of the knowledge of Allah and His sign and his heart is made the repository of the rare things of His knowledge and He intimates to him such secrets as He has kept hidden from others and He has selected him and drawn him towards Himself and guided him and raised him towards Himself and expanded his heart for the acceptance of these secrets and points of knowledge and made him a worker in His cause and inviter of Allah's servants to the path of virtue and warner against the chastisements of evil deeds and an argument of Allah in their midst, a guide and a rightly-guided man, an intercessor and one whose intercession has been accepted, a truthful man and one who verifies the truth of others, a deputy of Allah's prophets and messengers, on whom be the blessings of Allah.
So this man is the end and culminating point of mankind and there is not station above this, excepting that of prophethood. So it is your duty to beware that you do not oppose such a man and be averse to him and keep away from him and be hostile to him and avoid accepting him and being attentive towards what he says and admonishes. So verily safety lies in what such a man says and also in his company, and destruction and misguidance in what is besides him; except such men whom Allah gives power and assistance towards truth and mercy.
So I have divided mankind for you (into four divisions). Now you have to look at your own self if you have an observant mind and save yourself in the light of it if you are anxious to save it, having love for it. May Allah guide us and you towards what He loves and is pleased with, in this world and the hereafter!
From Futuh Al-Ghaib, 33rd Discourse by Abdul Qadir Jilani