Thought about your book when I read this passage in Thessalonians.
I Thessalonians 1:4-5 "Knowing, brethren beloved, your election of God. For our gospel came not unto you in word only, but also in power, and in the Holy Ghost, and in much assurance; as ye know what manner of men we were among you for your sake." (KJV)
I Thessalonians 1:4-5 "We know, dear brothers and sisters, that God loves you and has chosen you to be his own people. For when we brought you the Good News, it was not only with words but also with power, for the Holy Spirit gave you full assurance that what we said was true." (NLT)