My final word on this subject must of course come from The Word. Of course, you don't have to look far for biblical references to this subject. Jesus said that He is "the Way, the Truth, and the Life". If Christ is Truth, then it follows that lying must mean you are moving away from Christ. Being honest is about following in God's footsteps, for He cannot lie. My goal as a Christian is to become more God-like and God-centred, then honesty needs to be a focus. And that's honesty to myself as much as to my peers.
Luke 16:10 - Whoever can be trusted with very little can also be trusted with much, and whoever is dishonest with very little will also be dishonest with much.
Exodus 20:16 - You shall not give false testimony against your neighbour.
However, being honest is not always easy. It's so easy for man to wander off the narrow path, and kid yourself that you're still on course. Therefore, you need to work at being truthful, and it is often pretty hard work. We need to keep our eyes on Jesus all of the time.
Remember, you should strive not only to be honest to others, but honest to yourself as well. Therefore you should try to remain both humble and modest, however being too harsh on yourself is not being truthful. Also, thinking too highly of yourself is also dishonest. We need to find a balance before we can continue to grow.
Proverbs 11:3 - The integrity of the upright guides them, but the unfaithful are destroyed by their duplicity.
Romans 12:3 - For by the grace given me I say to every one of you: Do not think of yourself more highly than you ought, but rather think of yourself with sober judgment, in accordance with the measure of faith God has given you.
(all translations NIV)