Advice from Sufyan at-Thawri...

❝Be truthful at all times and in all places. Stay away from lying and from deception, and do not sit alongside liars and deceivers, for all such deeds are sins.

My brother, be careful not to show off, either in speech or in deed, for showing off is Shirk itself (Shirk being to associate partners with Allāh in worship).

Do not be conceited, for even a good deed is not raised (to the heavens) if any conceitedness is involved in it.

Take your religion only from one who is sincerely and compassionately concerned about his own religious guidance. The example of a scholar who is not concerned about his own religious well-being is that of a sick doctor: If he cannot treat his own disease…then how can he treat the diseases of others…? Likewise, if one is not concerned about his own religious well-being, then how can he be concerned about the religious well-being of others?

My brother, your religion is nothing more than your flesh and blood (i.e., You should be concerned about your religious well-being, because if you aren’t, it is your flesh and blood that will pay the penalty through the punishment of Allāh). Cry out of concern for your soul and have mercy on it; if you do not have mercy on it, then mercy will not be shown to it.

Sit only in the company of one who advises you to desire little from this world and who encourages you to put your hopes in the Hereafter. Take care not to sit with worldly people who speak constantly about worldly affairs; such people will ruin your religious well-being and will corrupt your heart.

Remember death frequently, and just as frequently ask Allāh to forgive you for your past sins.

Ask Allāh to keep you safe (safe from evil, from dangerous diseases, from trials and tribulations, etc) for the remainder of your life.

My brother, develop a good character and noble manners.

Do not act contrary to the Jama’ah, for goodness and safety are the consequences of being in harmony with the Jama’ah.

Someone who strives constantly for this world is like a person who builds one home and destroys another (because he builds prosperity for himself in this world, while he destroys all chances of becoming prosperous in the Hereafter).

Give sincere advice to every believer who asks you a question regarding his religion. And never hide good advice to someone who asks you about a matter that leads to the Good Pleasure of Allāh.

If you love your (Muslim) brother for the sake of Allāh, then give him generously from your self and your wealth.

Stay far away from arguments, quarrels, and disputes; otherwise, you will become a wrongdoer, a transgressor, and a deceiver.

Be patient at all times and in all places, for patience leads to righteousness, and righteousness leads to Paradise. Do not become angry and furious, for those two emotions lead to wickedness, and wickedness leads to the Hellfire.

Do not argue with a scholar, for that will lead to him loathing you. Being able to visit scholars (and learn from them) is a mercy, and cutting oneself off from them means that one is bringing down upon himself the wrath of Allāh. Verily, the scholars are the treasurers of the Prophets and are also their inheritors.

Turn away from worldly pleasures and things (to a certain degree), and, as a result, Allāh will enable you to see the faults and defects of this world.

Leave many of the things regarding which you are doubtful, and replace them with things regarding which you are not doubtful, and you will, as a result, remain safe: So by warding off doubt with certainty, you will remain safe in your religion.

Enjoin good and forbid evil — thus will you become loved by Allah.❞

[The Biography of Sufyān Ath-Thawrī, p.176-181]