This is why it is so important for us to read the verbatim teachings of the Apostles, and especially Peter, because this is the what the early church was taught. The epistles are letters written to the church for the purpose of answering questions, supplying advanced teaching, being of encouragement and rebuking wrong behaviour and doctrine. Nothing in the epistles overturns the teaching of the book of Acts. Rather, the epistles are the sequal to the teachings in the book of Acts. Almost evry epistle clearly states that it is written to a church and the saints within that church.
Saints is the scriptural term for persons saved under the plan of salvation within a dispensation.
As such it is safe to deduce that the epistles are not written to the unsaved. Rather, they are written to those who have already followed the salvation teachings found in the book of Acts. The last book of the New Testament is Revelation. There is no salvation scripture for the Dispensation of Grace found in this book. Rather, we learn about the coming end-times and the final resting places for the souls of the holy, righteous and wicked.