John Gill - Exposition
John Gill
That thou mightest know the certainty,.... The end the evangelist had in writing this Gospel, and sending it to Theophilus, was, that he might be more strongly assured of and more firmly established in the truths of the Gospel. The Vulgate Latin, Syriac, and Arabic versions render it, "that thou mightest know the truth"; that is, the certain truth of things: the truth he did in some measure know...