Paul gives Titus some characteristics to help him identify false teachers in verse 10 of chapter 1 and then opens verse 11 with a severe challenge. He says, “it’s necessary to silence them.” Jesus once said that it was “necessary” for Him to go to Jerusalem and die on the cross for the sins of all mankind. That 
Greek word is the same one used of Paul regarding muzzling the dangerous dogs who bring false teaching to God’s people. As it was necessary for Christ to die in order for salvation to come to mankind, it is also necessary to silence the lies that might prevent true salvation from coming to individuals. To believe in the doctrines of the false teachers that add something or take something away from the gospel message of Jesus Christ, is to be distracted by a wrong answer that will cause some to fail the test. The Gospel of Jesus is a simple message of salvation by grace through faith alone.
The issue that Paul is addressing and that the early church addressed as a whole is whether certain aspects of the Old Testament were essential ingredients for salvation along with faith in Jesus Christ. The issue is still very relevant today. Many churches attempt to promote a specific teaching by attaching it to the condition of “faith” expressed in the Gospel. You must believe and be baptized. You must believe and quite a specific sin. You must believe and etc., etc.. But the simplicity of the Gospel was given clearly to the Philippian jailor who fell on his knees and cried out with the question “what must I do to be saved?” Paul answered, “believe in the Lord Jesus Christ and you will be saved.”
John Piper quotes Romans 4:4-5 which says, ““To the one who works, his wages are not counted as a gift but as his due. And to the one who does not work but trusts him who justifies the ungodly, his faith is counted as righteousness.” He then writes, “For ‘the ungodly’—who know that they are riding the Titanic to destruction—the best news in all the world is the news that God will, by faith alone, count them as righteous because of Christ. This is the great ground of joy in the word of the cross: Justification is by grace alone (not mixed with our merit), through faith alone (not mixed with our works), on the basis of Christ alone (not mingling his righteousness with ours), to the glory of God alone (not ours).” Anyone who twists the scriptures to add another essential to the Good News of Jesus Christ must be silenced.
Chuck
“For I am not ashamed of the Gospel for it is the power of God leading to salvation for the Jew first and also for the gentile. For in it the righteousness of God is revealed from faith for faith, as it is written, ‘The righteous shall live by faith.’”