Catechism of the Catholic Church

"The sum of your word is truth; and every one of your righteous ordinances endures forever." "And now, O LORD God, you are God, and your words are true;" this is why God's promises always come true. God is Truth itself, whose words cannot deceive. This is why one can abandon oneself in full trust to the truth and faithfulness of his word in all things. The beginning of sin and of man's fall was due to a lie of the tempter who induced doubt of God's word, kindness, and faithfulness. (2465, 1063, 156, 397)