A true witness delivers souls, but a deceitful witness speaks lies. (Proverbs 14:25)
In the sixth chapter of Proverbs we are told that there are seven things that are an abomination to the Lord. One of those things is, "A false witness who speaks lies." We do not need to exaggerate the truth of the gospel of Jesus Christ, nor do we need to embellish our testimonies to win the lost. We need not be "Evang-elastic." Likewise few people are won to Christ through complex theological analysis. They are won by the good news of the simplicity of the gospel of Jesus Christ. We are to be true witnesses: with our words, our actions, our deeds and our very demeanor. It is a lie to talk about Jesus with coworkers when you should be working. It is a lie to testify in one hand of your love for Him when with the other hand you are robbing Him of His tithes and offerings. I can imagine that people have been won to Christ by the words of a liar, but I can assure you that they have not matured by the words of a liar.