Luke 1:4

4 that thou mightest know the certainty of those things in which thou hast been instructed.

Luke 1:4 In-Context

2 as those who from the beginning were eye-witnesses of and attendants on the Word have delivered them to us,
3 it has seemed good to *me* also, accurately acquainted from the origin with all things, to write to thee with method, most excellent Theophilus,
4 that thou mightest know the certainty of those things in which thou hast been instructed.
5 There was in the days of Herod, the king of Judaea, a certain priest, by name Zacharias, of the course of Abia, and his wife of the daughters of Aaron, and her name Elizabeth.
6 And they were both just before God, walking in all the commandments and ordinances of the Lord blameless.
The Darby Translation is in the public domain.