King James Bible
"That thou mightest know the certainty of those things, wherein thou hast been instructed."
Luke states his purpose: to provide Theophilus with verified assurance about the Christian faith. The Greek word for 'certainty' (asphaleia) implies unshakeable security, indicating Luke's intent to move his reader from secondhand knowledge to firm conviction through his orderly account. Theophilus had already received Christian teaching (likely oral catechesis common in the early church), but Luke aims to strengthen this foundation with written testimony. This reveals the Gospel's role as a confirming document for those already exposed to the faith's basic teachings.