A.T. Robertson Commentary Acts 26:18

"to open their eyes, that they may turn from darkness to light and from the power of Satan unto God, that they may receive remission of sins and an inheritance among them that are sanctified by faith in me." — Acts 26:18 (ASV)

To open (ανοιξα). First aorist active infinitive of purpose.

That they may turn (του επιστρεψα). Another infinitive of purpose first aorist active (genitive case and articular), epexegetic to ανοιξα.

That they may receive (του λαβειν). Another genitive articular infinitive of purpose subordinate (epexegetic) to του επιστρεψα.

Sanctified by faith in me (ηγιασμενοις πιστε τη εις εμε). Perfect passive participle of αγιαζω, instrumental case of πιστε, article before εις εμε ("by faith, that in me"). These important words of Jesus to Paul give his justification to this cultured audience for his response to the command of Jesus. This was the turning point in Paul's career and it was a step forward and upward.