Anyone who calls upon the name of the Lord will be saved. But how shall they ask Him to save them unless they believe in Him? And how can they believe in Him if they have never heard about Him? And how can they hear about Him unless someone tells them?-Romans 10:13,14

Confirming your witness through your life doesn’t replace your verbal witnessing, though. Both are needed. You cannot just live a Christian life and hope that others will notice; they may notice that you life a good life, but they won’t know why. Jesus lived a perfect life and He was constantly proclaiming the gospel. Jesus’ command is to witness by word and deed.