The Bible tells us in many places to avoid lying. It’s one of the Ten Commandments–
“You shall not bear false witness against your neighbor” Exodus 20:16
It’s also mentioned in the book of Proverbs…
“Lying lips are an abomination to the Lord, but those who act faithfully are his delight.” Proverbs 12:22
and in the New Testament as well.
“Therefore, having put away falsehood, let each one of you speak the truth with his neighbor, for we are members of one another. Ephesians 4:25
Here’s a quote from my devotional reading that explains how to avoid this particular sin:
“It seems to me, that the shortest way to check the darker forms of deceit is to set watch more scrupulous against those which have mingled, unregarded and unchastised with the current of our life. Do not let us lie at all. Do not think of one falsity as harmless, and another as slight, and another as unintended. Cast them all aside; they may be light and accidental; but they are an ugly soot from the smoke of the pit, for all that; and it is better that our hearts should be swept clean of them, without over care as to which is largest or blackest. Speaking truth is like writing fair, and comes only by practice; it is less a matter of will than of habit, and I doubt if any occasion can be trivial which permits the practice and formation of such a habit.“
Of course, keep in mind that speaking the truth is not to be used as an excuse for hurting others with comments that are overly blunt or even cruel. Paul also tells us to speak the truth “in love”(Ephesians 4:15) and Peter exhorts us to use “gentleness and respect.”(1 Peter:3:15).
Use words that are both truthful and loving. Make this your habit.