Mu'jam Kabir Tabarani 8490 — about Sayyiduna Abdullah bin Mas'ud

It is narrated about Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that he would come every Thursday and stand up, not sitting down, and say: "Do not put people to trial, for among them are the weak, the elderly and the needy." Then he would say: It is a matter of two things. The best way is the way of Muhammad (peace and blessings be upon him), the most truthful word is the Book of Allah, the worst of things are newly invented matters, and every newly invented thing is misguidance. The wretched one is he who was written as wretched while still in his mother's womb, and the fortunate one is he who takes admonition from the state of others. Beware! Let not the term become long for you, and let not hope distract you, for everything that is coming is near, and the far is only that which is not coming. Among the worst of people are those who prolong the day out of fear of the night. Indeed, killing a believer is disbelief (kufr), and insulting him is sinfulness (fusuq), and it is not lawful for a Muslim to cut off his brother for more than three days. Beware! The worst narration is lying, and lying is not right, neither in earnest nor in jest, nor that a man makes a promise to his child and does not fulfil it. Beware! Lying leads to wickedness, and wickedness leads to Hell; and truthfulness leads to righteousness, and righteousness leads to Paradise. It is said of the truthful one: "He spoke the truth and acted righteously," and it is said of the liar: "He lied and acted wickedly."
And I heard the Messenger of Allah (peace and blessings be upon him) say: "A servant speaks the truth until he is written with Allah as a siddiq (truthful one), and he keeps lying until he is written with Allah as a great liar. Do you know what 'adh (slanderous lying) is? It is tale-bearing that causes corruption among people."