How many Christians, in certain circumstances, ever feel ashamed or embarrassed for being a Christian? Sadly, that number would be rather high, and it is not merely limited to those who are 
young in age or young in the faith. Even older Christians admit that there are times when they feel uncomfortable to admit and stand up for their Christian faith.
Perhaps this is why the Psalms and the New Testament epistles give so much emphasis to not being ashamed. David prayed repeatedly, “O my God, I trust in You; Let me not be ashamed” (Psa. 25:2; 31:17; 119:46, 116). Paul often wrote, “In nothing shall I be ashamed” (Rom. 1:16; Phil. 1:20; 2 Tim. 1:12), and he urged his readers, “Do not be ashamed” (2 Tim. 1:8), for a faithful Christian “does not need to be ashamed” (2 Tim. 2:15). Peter urged, “If anyone suffers as a Christian, let him not be ashamed, but let him glorify God in this matter” (1 Pet. 4:16).
How can I fight back any inclination to be ashamed? “Trust” in the Lord (Psa. 25:2). “Speak” often of His word (Psa. 119:46). Focus on salvation (Rom. 1:16). Remember in “whom [you] have believed” (2 Tim. 1:12). Let the wicked be ashamed of themselves (Psa. 31:17).