2Timothy 1:16
"The Lord give mercy unto the house of Onesiphorus; for he oft refreshed me, and was not ashamed of my chain:"
There is no doubt that the Apostle Paul emphasized not being ashamed. Seven times throughout the Pauline epistles you will see that Paul announced he was not ashamed. Before Paul was saved, he was not ashamed of his beliefs. When he got saved that strong belief system caused him not to be ashamed of Christ.