As we Christians go about our daily lives, we are constantly confronted with lies and deceits. It is important that we do not participate in such falsehoods or dishonesty. Even small "white lies" told in a spirit of kindness should never pass our lips.
Jesus was the Truth. He explicitly told us: " ….I am the way, the truth, and the life …." John 14:6 And He referred to His return as the Holy Spirit as the Truth: "Howbeit when he, the Spirit of truth, is come, he will guide you into all truth …." John 16:13
Jesus was the Truth, and He expects no less from us. So let His Spirit "guide you into all truth," the whole truth, and nothing but the truth. Make truth your policy.
Being a Truth Teller isn’t easy. Lots of people aren’t ready to hear it, and will resent you for it. We live in a world of lies and liars. Most people live their lives that way, and are accustomed to it. Often when you tell the truth, your listeners are twice offended. Firstly to hear the Truth itself, and secondarily because you have violated their social norm of lying to smooth things over. They resent not being lied to.
Finally, you must consider the issue of silence. If you are in a situation where your silence would be interpreted as supporting a lie, you must speak up with the truth. Lies may be implied by silence.
The Bible tells us we are made in God's image. Think of your image as a statue. Each time you tell a lie, a little piece gets chipped off. After some time, and many lies, God is no longer recognizable in your image. It would be a shame to let that happen.
So, stay in the image of God. Stick to the truth in all things.