The Bible is clear, 'we overcome by the blood of the Lamb and the word of our testimony. We note the power of our testimony from this and other Scriptures.
However, you can be assured that there will be a battle over your testimony. Circumstances may seem to be obstacles. Temptation may increase in intensity. Friends may turn a cold shoulder because they are jealous of your forward momentum in Christ. Family may not understand and still you as the 'carpenter's son.' Personal insecurities and past failures are not friends either and the devil will whisper these lies.
But for whatever challenges come your way to upend your testimony, you must not waver, you must contend for your testimony to last. You must fight the good fight. You are a new creation in Christ Jesus, the old things are passed away. Believe this by faith and declare your victory in Christ.
Know this, you will have the power of God inside you, the hope of glory, the same Spirit who raised Jesus from the dead, to help you keep and maintain your testimony to the glory of God. The greatest power the world has ever known resides within the believer. Be encouraged. Publish your testimony!