NCVLuke 1:4to help you know that what you have been taught is true.Zechariah and Elizabeth
AMPLuke 1:4[My purpose is] that you may know the full truth and understand with certainty and security against error the accounts (histories) and doctrines of the faith of which you have been informed and in which you have been orally instructed.
EASLuke 1:4People have already taught you about these things. Now you can be sure that they are true.