1:1-4. Luke will not write of things about which Christians may safely differ from one another, and hesitate within themselves; but the things which are, and ought to be surely believed. The doctrine of Christ is what the wisest and best of men have ventured their souls upon with confidence and satisfaction. And the great events whereon our hopes depend, have been recorded by those who were from the beginning eye-witnesses and ministers of the word, and who were perfected in their understanding of them through Divine inspiration.
4. that thou mightest know—"know thoroughly."
hast been instructed—orally instructed—literally, "catechized" or "catechetically taught," at first as a catechumen or candidate for Christian baptism.