Adhere to truthfulness
‘Abdullāh ibn Mas‘ūd (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: “Adhere to truthfulness, for truthfulness leads to righteousness and right eousness leads to Paradise. A man will keep speaking the truth and striving to speak the truth until he will be recorded with Allah as the most truthful. Beware of lying, for lying leads to wickedness and wickedness leads to Hell fire. A man will keep telling lies and striving to tell lies until he is recorded with Allah as the most liar."
The Prophet (may Allah's peace and blessings be upon him) urged Muslims to be truthful at all times, and clarified its good consequences in this world and in the Hereafter. Truthfulness is the foundation of righteousness which is the road to Paradise. If a man is keen on being truthful, he will be labeled among the truthful in the sight of Allah, which predicts a good and safe ending for him. The Prophet (may Allah's peace and blessings be upon him) also warned from lying and clarified its harm and evil consequences. Lying is the foundation of wickedness which is the road to Hellfire.