“…But let your ‘Yes’ be ‘Yes,’ and your ‘No,’ ‘No,’ lest you fall into judgment” (James 5:12).
Being truthful and a person of your word is of great importance to God, because He does not break His covenant, alter the word which goes from His lips, or lie (Psalm 89:34-35).
Saying what you mean and meaning exactly what you say is an indicator that you love and respect truth. It is wholly unlike Satan—a liar and the father of lies—who does not stand in the truth because there is no truth in him (John 8:44).
Saying what you mean and meaning exactly what you say is an indicator of love and respect for others. Flattery tells others what they want to hear, regardless of its accuracy. Speaking the truth in love communicates to others what is accurate, regardless of the consequences.
Saying what you mean and meaning exactly what you say is necessary to fellowship with God and a stable life (Psalm 15).
Jehovah is the God of truth (Psalm 31:5; Isaiah 65:16). To prioritize Him and His righteousness (Matthew 6:33) you must prioritize truthfulness and integrity.