Truthfulness is one’s promises and fulfilling them. truthfulness covers various aspects: 1) Truthfulness in one’s speech. 2) Truthfulness in one’s intention and desire. 3) Trustfulness in one’s promises and fulfilling them 4) Truthfulness in one’s determination 5) Truthfulness in one’s action, where his outward and inward are the same, such as humbleness in prayer. 6) Truthfulness in fulfilling the different aspects of the religion.
This is the highest level, such as truthfulness in one’s fear, hope, asceticism, pleasure, trust, love and the rest of the actions of the heart. Whoever is truthful in all of what was previously mentioned then he is the truthful one because he has truly reached the level of the truthful one, The Prophet (PBUH) said: “Be truthful, for truthfulness leads to righteousness, and righteousness leads to Paradise: And a man keeps on telling the truth until he becomes a truthful person.
Falsehood leads to Al-Fajur (i.e. wickedness, evil-doing), and Al-Fajur (wickedness) leads to the (Hell) Fire, and a man may keep on telling lies till he is written before Allah, a liar.” (al-Bukhari and Muslim).
Whoever is confused about what is true from that which is false and is truthful in seeking the truth, without following his desires then it is likely that he is going to be successful in his search. If he is not, then Allah will excuse him. Lying opposes being truthful. The first thing lying reaches to and corrupts in a person is the tongue then the limbs, and it does the same as it did to the tongue.
After that, it spreads and becomes a part of all of his saying, actions and all of his affairs until he becomes surrounded by it.
Intentions as the actions of the heart